Core Connections Integrated 1
Core Connections Integrated 1
2nd Edition
Brian Hoey, Judy Kysh, Leslie Dietiker, Tom Sallee
ISBN: 9781603283236
Textbook solutions

All Solutions

Page 487: Closure Activity

Exercise 126
Solution 1
Solution 2
Step 1
1 of 3
$textbf{color{#4257b2}ARITHMETIC:}$

Since the graph of an arithmetic sequence is a line when the terms are connected, then we can find an equation for the arithmetic sequence using the slope-intercept form of a line:

$$
y=mx+b
$$

or in this case,

$$
t(n)=mn+t(0)
$$

Representing the two terms as points, we have $(1,8)$ and $(7,512)$ so the slope is:

$$
m=dfrac{Delta y}{Delta x }=dfrac{512-8}{7-1}=dfrac{504}{6}=84
$$

This is also the sequence generator.

To find $t(0)$, use the slope and either of the two points. I used $(1,8)$:

$$
begin{align*}
8&=84 (1)+t(0)\
8&=84+t(0)\
-76&=t(0)\
end{align*}
$$

So, the equation for the arithmetic sequence is:

$$
color{#c34632}t(n)=84n-76
$$

Step 2
2 of 3
$textbf{color{#4257b2}GEOMETRIC:}$

Since the graph of a geometric sequence is an exponential graph when the terms are connected, then we can use the exponential equation:

$$
y=acdot b^x
$$

or in this case,

$$
t(n)= t(0)cdot b^n
$$

Using $t(1)=8$, we write one equation:

$$
8=t(0)btag{1}
$$

Using $t(7)=512$, we write another equation:

$$
512=t(0)b^7tag{2}
$$

Solve for $t(0)$ using eq. (1) to obtain:

$$
dfrac{8}{b}=t(0) tag{3}
$$

Substitute eq. (3) to eq. (2) then solve for $b$:

$$
begin{align*}
512&=dfrac{8}{b}cdot b^7\
512&=8 b^6\
64&=b^6\
2^6&=b^6\
2&=b
end{align*}
$$

Solve for $t(0)$ using eq. (3):

$$
t(0)=dfrac{8}{2}=4
$$

So, the equation for the geometric sequence is:

$$
color{#c34632}t(n)= 4(2)^n
$$

Result
3 of 3
arithmetic: $t(n)=84n-76$

geometric: $t(n)=4(2)^n$

Step 1
1 of 2
First, we will calculate $d$ for the arithmetic sequence:

$$
t(7)=t(1)+6d
$$

$$
512=8+6d
$$

$$
6d=504
$$

$$
d=84
$$

So, we get the following arithmetic sequence:

$$
{t}_{n}=begin{cases}
8, & {n}=1\
8+(n-1)84, & {n}>1\
end{cases}
$$

Now, we will create geometric sequence in the following way:

$$
t(7)=t(1)q^6
$$

$$
512=8q^6
$$

$$
q^6=64
$$

$$
q=2
$$

So, we get the following geometric sequence:

$$
{t}_{n}=begin{cases}
8, & {n}=1\
8(2)^{n-1}, & {n}>1\
end{cases}
$$

Result
2 of 2
$$
{t}_{n}=begin{cases}
8, & {n}=1\
8+(n-1)84, & {n}>1\
end{cases}
$$

$$
{t}_{n}=begin{cases}
8, & {n}=1\
8(2)^{n-1}, & {n}>1\
end{cases}
$$

Exercise 127
Step 1
1 of 2
Let $x$ be the number of hours and $y$ be the cost.

Divide the domain in intervals of 1. For $0leq xleq 1$, $y=2$. For $1< xleq 2$, $y=2+0.50=2.50$. For $2< xleq 3$, $y=2.50+0.50=3$. Continue this pattern for the other intervals. For $leq$, use a closed circle at the endpoint and for $<$, use an open circle at the endpoint. The step graph should look like:

Exercise scan

Result
2 of 2
Hint: Divide the domain in intervals of 1.
Exercise 128
Step 1
1 of 3
Note: In the exponential equation $f(x)=ab^x$, $a$ is the initial value and $b$ is the multiplier.

$textbf{a.}$

There is an annual (or yearly) appreciation so the appropriate unit of time is $text{textcolor{#c34632}{Years}}$.

An annual appreciation is an increase so the multiplier is:

$$
b=100%+6%=106%=color{#c34632}1.06
$$

The initial value is $a=color{#c34632}120000$ (dollars).

Let $x$ be the number of years and $y$ (or $f(x)$) be the price of the house in dollars. Using the values of $a$ and $b$, the exponential equation is:

$$
color{#c34632}f(x)= 120000(1.06)^x
$$

$textbf{b.}$

The rate is per hour so the appropriate unit of time is $text{textcolor{#c34632}{Hours}}$.

The number of bacteria increases so the multiplier is:

$$
b=100%+22%=122%=color{#c34632}1.22
$$

The initial value is $a=color{#c34632}180$.

Let $x$ be the number of hours after noon and $y$ (or $f(x)$) be the number of bacteria. Using the values of $a$ and $b$, the exponential equation is:

$$
color{#c34632}f(x)= 180(1.22)^x
$$

Step 2
2 of 3
$textbf{c.}$

The rate is per year so the appropriate unit of time is $text{textcolor{#c34632}{Years}}$.

A depreciation is a decrease so the multiplier is:

$$
b=100%-11%=89%=color{#c34632}0.89
$$

The initial value is $a=color{#c34632}12250$ (dollars).

Let $x$ be the number of years and $y$ (or $f(x)$) be the price of the value of the car. Using the values of $a$ and $b$, the exponential equation is:

$$
color{#c34632}f(x)= 12250 (0.89)^x
$$

$textbf{d.}$

Since the compounding is monthly, the appropriate unit of time is $text{textcolor{#c34632}{Months}}$.

First, we find the monthly interest rate: $6%div 12=0.5%$. The investment increases so the multiplier is:

$$
b=100%+0.5%=100.5%=color{#c34632}1.005
$$

The initial value is $a=color{#c34632}1000$ (dollars).

Let $x$ be the number of months and $y$ (or $f(x)$) be the amount of investment in dollars. Using the values of $a$ and $b$, the exponential equation is:

$$
color{#c34632}f(x)= 1000 (1.005)^x
$$

Result
3 of 3
a. Years ; 1.06 ; 120000 ; $f(x)=120000(1.06)^x$

b. Hours ; 1.22 ; 180 ; $f(x)=180(1.22)^x$

c. Years ; 0.89 ; 12250 ; $f(x)=12250 (0.89)^x$

d. Months ; 1.005 ; 1000 ; $f(x)=1000(1.005)^x$

Exercise 129
Step 1
1 of 4
$$
{color{#4257b2}text{ a) }}
$$

$$
begin{align*}
&text{Subtract 3y from both sides}\
&2x+3y-3y=6-3y\\
&2x=6-3y tag{Simplify} \
&frac{2x}{2}=frac{6}{2}-frac{3y}{2} tag{Divide both sides by 2}\\
&boxed{{color{#c34632} x=frac{6-3y}{2} } }
end{align*}
$$

Step 2
2 of 4
$$
{color{#4257b2}text{ b) }}
$$

$$
begin{align*}
&text{Add 3 to both sides}\
&FM-3+3=Q+3\\
&FM=Q+3 tag{Simplify} \
&frac{FM}{M}=frac{Q}{M}+frac{3}{M};quad :Mne :0 tag{Divide both sides by M}\\
&boxed{{color{#c34632} F=frac{Q+3}{M} } }
end{align*}
$$

Step 3
3 of 4
$$
{color{#4257b2}text{ c) }}
$$

$$
begin{align*}
&text{Subtract a from both sides}\
&frac{r}{s}+a-a=2b-a\\
&frac{r}{s}=2b-a tag{Simplify} \
&frac{rs}{s}=2bs-as;quad :sne :0 tag{Multiply both sides by s}\\
&boxed{{color{#c34632} r=2bs-as } }
end{align*}
$$

Result
4 of 4
$$
color{#4257b2} text{a)}x=frac{6-3y}{2}
$$

$$
color{#4257b2} text{b)} F=frac{Q+3}{M}
$$

$$
color{#4257b2} text{c)}r=2bs-as
$$

Exercise 130
Step 1
1 of 2
Find the coordinate of mid point for the following points.

$$
color{#4257b2}text{(a)} (-3, 11) (5, 6)
$$

Midpoint means the midpoint for $x, y$ as follows:

Midpoint for $x$ axis as follows:

$$
dfrac{-3+5}{2}=dfrac{2}{2}=1
$$

Midpoint for $y$ axis as follows:

$$
dfrac{11+6}{2}=dfrac{17}{2}=8.5
$$

The midpoint for the above points is $(1, 8.5)$.

Find the coordinate of mid point for the following points.

$$
color{#4257b2}text{(b)} (-4, -1) (8, 9)
$$

Midpoint means the midpoint for $x, y$ as follows:

Midpoint for $x$ axis as follows:

$$
dfrac{-4+8}{2}=dfrac{4}{2}=2
$$

Midpoint for $y$ axis as follows:

$$
dfrac{-1+9}{2}=dfrac{8}{2}=4
$$

The midpoint for the above points is $(2, 4)$.

Result
2 of 2
$$
text{color{#4257b2}(a) $(1, 8.5)$ (b) $(2, 4)$}
$$
Exercise 131
Step 1
1 of 5
#### (a)

On the following picture, there is graphed quadrilateral $MNPQ$.

Exercise scan

Step 2
2 of 5
Now, we will find slopes.

$$
text{slope}overline{MN}=dfrac{-2-1}{2-7}=dfrac{3}{5}
$$

$$
text{slope}overline{NP}=dfrac{3+2}{-1-2}=-dfrac{5}{3}
$$

Because slope $overline{MN}cdottext{slope}overline{NP}=-1$, we can conclude that $measuredangle MNP=90^{circ}$.

#### (b)

We can conclude that all angles are $90^{circ}$, so, $MNPQ$ is actually rectangle.

#### (c)

We will find first the length of diagonal $overline{NQ}$:

$$
overline{NQ}=sqrt{(6+2)^2+(4-2)^2}=sqrt{68}
$$

Now, we will calculate the length of diagonal $overline{MP}$.

$$
overline{MP}=sqrt{(3-1)^2+(-1-7)^2}=sqrt{68}
$$

We can notice that lengths of those diagonals are equal.

Step 3
3 of 5
#### (d)

From the following picture, we can notice that midpoint of $overline{MN}$ is $A(-0.5,4.5)$.

Exercise scan

Step 4
4 of 5
#### (e)

Because of this rectangle with all equal sides, or square, it is enough to find the length of one side in order to calculate its perimeter an area.

$$
overline{MN}=sqrt{(-2-1)^2+(2-7)^2}=5
$$

So, the perimeter is:

$$
O=4cdot5=20
$$

The area is:

$$
P=5^2=25
$$

Result
5 of 5
a) $measuredangle MNP=90^{circ}$, slope$overline{NP}=-dfrac{5}{3}$; b) Rectangle; c) Length of diagonals are equal; d) $A(-0.5, 4.5)$; e) $O=20$, $P=25$
Exercise 132
Step 1
1 of 2
The required meaning is that after at the beginning there is $120$ ppm drug remaining in the bloodstream, and it decreases at the rate $0.997$ per minute.

In order to calculate does more than half the drug remain after $4$ hours, we will substitute $4h=240$ minutes for $t$ in the equation and solve it for $y$:

$$
y=120(0.997)^{240}
$$

$$
y=58.35
$$

The conclusion is that after $4$ hours there is less than half the drug remain in the bloodstream.

Result
2 of 2
There is less than half the drug remain.
Exercise 133
Step 1
1 of 2
$$
text{color{#4257b2}(a) What will it cost in $10$ years?}
$$

Put the given information in standard form of exponent equation as follows:

$$
y=a b^x y=3.89 (1.05)^x
$$

$$
y=3.89(1.05)^10 y=3.89cdot1.6288 y=6.3364
$$

Cost it in $10$ years will be $6.3364$ dollars.

$$
text{color{#4257b2}(b) What did it cost $5$ years ago?}
$$

Put the given information in standard form of exponent equation as follows:

$$
y=a b^x y=3.89 (1.05)^x
$$

$$
y=3.89(1.05)^{-5} y=dfrac{3.89}{1.05^5} y=dfrac{3.89}{1.2763}
$$

$$
y=3.0478
$$

Cost it in $5$ years ago was $3.0478$ dollars.

Result
2 of 2
$$
text{color{Brown}(a) $6.3364$ dollars (b) $3.0478$ dollars}
$$
Exercise 134
Step 1
1 of 2
Let:

$$
begin{align*}
a&totext{number of adult tickets sold}\
s&totext{number of student tickets sold}\
end{align*}
$$

Set up the equations.

There were 10 people so we write:

$$
a+s=10tag{1}
$$

A total of $$186.50$ were paid:

$$
24.95a+15.95s=186.50tag{2}
$$

Using eq. (1), solve for $s$ to obtain the equation:

$$
s=10-atag{3}
$$

Use the Substitution Method by substituting eq. (3) to eq. (2) and solve for $a$:

$$
begin{align*}
24.95a+15.95(10-a)&=186.50\
24.95a+159.5-15.95a&=186.50\
9a+159.5&=186.50\
9a&=27\
a&=3
end{align*}
$$

So, there were $text{color{#c34632}3 adults.}$

Result
2 of 2
3 adults
Exercise 135
Step 1
1 of 3
Determine if the triangles are congruent or not.

$color{#4257b2}text{(a) First figure}$.

The upper triangle

$$
text{The third length}=8^+6^=64+36=100
$$

Use square root property as follows:

$$
=sqrt{100}=10
$$

The lower triangle

$$
text{The third length}=10^2-8^2=100-36=64
$$

Use square root property as follows:

$$
=sqrt{64}=8
$$

$because$ The all sides in the triangles are equals.

$therefore$ The two triangles are congruent.

$color{#4257b2}text{(b) Second figure}$.

$because$ There are two angles in both of triangles are equals.

$because$ There is one side length in both of triangles is equal.

$therefore$ The two triangles are congruent.

Step 2
2 of 3
$color{#4257b2}text{(c) Third figure}$.

$because$ There is one angle in both of triangles is equal.

$because$ There is two side lengths in both of triangles are equals.

$therefore$ The two triangles are congruent.

$color{#4257b2}text{(d) Forth figure$$}$.

$because$ There is one angle in both of triangles is equal.

$because$ There is two side lengths in both of triangles are equals.

$therefore$ The two triangles are congruent.

Result
3 of 3
$$
text{color{#4257b2}Four figures are equals}
$$
Exercise 136
Solution 1
Solution 2
Result
1 of 1
Possible answer: Most likely, you will feel confident about questions that are already familiar from previous courses like solving a system of equations in one or two variables, evaluating exponents, finding equations of lines, and finding a line of best fit. You may find the lessons in this chapter to be hard (or simply tedious) since it may be your first time answering such problems but with practice and in time, you will eventually find them easy to solve.
Step 1
1 of 2
After you solve all problems, you can check your answers using a table of answers at the end of the chapter and see if you have a problem with some tasks.
Result
2 of 2
You can check your answers at the end of chapter.
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