Reviewing Equations

Site: Saylor Academy
Course: GKT101: General Knowledge for Teachers – Math
Book: Reviewing Equations
Printed by: Guest user
Date: Sunday, May 19, 2024, 6:08 PM

Description

This lecture series explains the difference between an equation and an algebraic expression. It also defines what it means to solve an equation. Watch the videos and complete the interactive exercises.

Testing solutions to equations

Testing solutions to equations - Questions

1. Select all the equations where y = 10 is a solution.

Choose 2 answers:

A. y+11=22

B. 8=18−y

C. 60=6y

D. \frac{y}{5}=4

E. 10y=20


2. Which value of f makes 3f+5=32 a true statement?

Choose 1 answer:

A. f = 6

B. f = 8

C. f = 9

D. f = 12


3. Select all the equations where m = 4 is a solution.

Choose 3 answers:

A. 13=9+m

B. 7−m=3

C. 15=11m

D. 5=m+2

E. 20÷m=5


4. Which value of h makes \frac{8+h}{10}=1 a true statement?

Choose 1 answer:

A. h = 1

B. h = 2

C. h = 3

D. h = 4


5. Select all the equations where b = 11 is a solution.

Choose 2 answers:

A. 2b=211

B. b+18=7

C. 77=7b

D. 9=b−2

E. 11=33÷b


6. Which value of g makes 26=7(g-9)+12 a true statement?

Choose 1 answer:

A. g = 11

B. g = 12

C. g = 13

D. g = 14


7. Select all the equations where c = 9 is a solution.

Choose 2 answers:

A. 4-c=5

B. 20=14+c

C. 15=c-6

D. \frac{c}{3}= 3

E. 36=4c

Answers

1.

B. 8=18−y

C. 60=6y


For each equation, y = 10 is a solution if it makes the equation true.

To test the each equation, we can follow these steps:

  1. Substitute y= 10 into the equation.
  2. Simplify.
  3. Check if both sides of the equation have the same value.

For example, here's how we could test the first equation:

\begin{array}{r}
y+11=22 \\
10+11 \stackrel{?}{=} 22 \\
21 \neq 22
\end{array}

No, y =10 is not a solution.

y =10 is a solution for the following equations:

  • 8=18−y
  • 60=6y


2.

C. f = 9


Let's substitute each f value into the equation to see if it is a solution.

Let's substitute f = 6 and see if the equation is true.

\begin{array}{r}
3(f)+5=32 \\
3(6)+5 \stackrel{?}{=} 32 \\
18+5 \stackrel{?}{=} 32 \\
23 \neq 32
\end{array}

No, f = 6 does not make a true statement.


Let's substitute f = 8 and see if the equation is true.

\begin{array}{r}
3(f)+5=32 \\
3(8)+5 \stackrel{?}{=} 32 \\
24+5 \stackrel{?}{=} 32 \\
29 \neq 32
\end{array}

No, f = 8 does not make a true statement.


Let's substitute f = 9 and see if the equation is true.

\begin{array}{r}
3(f)+5=32 \\
3(9)+5 \stackrel{?}{=} 32 \\
27+5 \stackrel{?}{=} 32 \\
32 \stackrel{\checkmark}{=} 32
\end{array}

Yes, f = 9 does make a true statement.


Let's substitute f = 12 and see if the equation is true.

\begin{array}{r}
3(f)+5=32 \\
3(12)+5 \stackrel{?}{=} 32 \\
36+5 \stackrel{?}{=} 32 \\
41 \neq 32
\end{array}

No, f = 12 does not make a true statement.

The f value that makes 3f+5=32 a true statement is f = 9 .


3.

A. 13=9+m

B. 7−m=3

E. 20÷m=5


For each equation, m = 4 is a solution if it makes the equation true.

To test the each equation, we can follow these steps:

  1. Substitute  m = 4 into the equation
  2. Simplify.
  3. Check if both sides of the equation have the same value.

For example, here's how we could test the first equation:

\begin{aligned}
&13=9+m \\
&13 \stackrel{?}{=} 9+4 \\
&13 \stackrel{\checkmark}{=} 13
\end{aligned}

Yes,  m = 4 is a solution.

m = 4 is a solution for the following equations:

  • 13=9+m
  • 7−m=3
  • 20÷m=5


4.

B. h = 2


Let's substitute each h value into the equation to see if it is a solution.

Let's substitute h = 1 and see if the equation is true.

\begin{aligned}
\frac{8+h}{10} &=1 \\
\frac{8+1}{10} & \stackrel{?}{=} 1 \\
\frac{9}{10} & \stackrel{?}{=} 1 \\
\frac{9}{10} & \neq 1
\end{aligned}

No, h = 1 does not make a true statement.


Let's substitute h = 2 and see if the equation is true.

\begin{array}{r}
\frac{8+h}{10}=1 \\
\frac{8+2}{10} \stackrel{?}{=} 1 \\
\frac{10}{10} \stackrel{?}{=} 1 \\
1 \stackrel{\checkmark}{=} 1
\end{array}

Yes, h = 2 does make a true statement.


Let's substitute h = 3 and see if the equation is true.

\begin{array}{r}
\frac{8+h}{10}=1 \\
\frac{8+3}{10} \stackrel{?}{=} 1 \\
\frac{11}{10} \stackrel{?}{=} 1 \\
\frac{11}{10} \neq 1
\end{array}

No, h = 3 does not make a true statement.


Let's substitute h = 4 and see if the equation is true.

\begin{array}{r}
\frac{8+h}{10}=1 \\
\frac{8+4}{10} \stackrel{?}{=} 1 \\
\frac{12}{10} \stackrel{?}{=} 1 \\
\frac{6}{5} \neq 1
\end{array}

No, h = 4 does not make a true statement.

The h-value that makes \frac{8+h}{10}=1 a true statement is h =2 .


5.

C. 77=7b

D. 9=b−2


For each equation, b = 11 is a solution if it makes the equation true.

To test the each equation, we can follow these steps:

  1. Substitute b = 11 into the equation.
  2. Simplify.
  3. Check if both sides of the equation have the same value.


For example, here's how we could test the first equation:

\begin{array}{r}
2 b=211 \\
2 \times 11 \stackrel{?}{=} 211 \\
22 \neq 211
\end{array}

No, b = 11 is not a solution.

b = 11 is a solution for the following equations:

  • 77=7b
  • 9=b−2


6.

A. g = 11


Let's substitute each g-value into the equation to see if it is a solution.

Let's substitute g = 11 and see if the equation is true.

\begin{aligned}
&26=7(g-9)+12 \\
&26 \stackrel{?}{=} 7(11-9)+12 \\
&26 \stackrel{?}{=} 7(2)+12 \\
&26 \stackrel{?}{=} 14+12 \\
&26 \stackrel{\checkmark}{=} 26
\end{aligned}

Yes, g = 11 does make a true statement.


Let's substitute g = 12 and see if the equation is true.

\begin{aligned}
&26=7(g-9)+12 \\
&26 \stackrel{?}{=} 7(12-9)+12 \\
&26 \stackrel{?}{=} 7(3)+12 \\
&26 \stackrel{?}{=} 21+12 \\
&26 \neq 33
\end{aligned}

No, g = 12 does not make a true statement.


Let's substitute g = 13 and see if the equation is true.

\begin{aligned}
&26=7(g-9)+12 \\
&26 \stackrel{?}{=} 7(13-9)+12 \\
&26 \stackrel{?}{=} 7(4)+12 \\
&26 \stackrel{?}{=} 28+12 \\
&26 \neq 40
\end{aligned}

No, g = 13 does not make a true statement.


Let's substitute g = 14 and see if the equation is true.

\begin{aligned}
&26=7(g-9)+12 \\
&26 \stackrel{?}{=} 7(14-9)+12 \\
&26 \stackrel{?}{=} 7(5)+12 \\
&26 \stackrel{?}{=} 35+12 \\
&26 \neq 47
\end{aligned}

No, g = 14 does not make a true statement.

The g- value that makes 26=7(g-9)+12 a true statement is g = 11.


7.

D. \frac{c}{3}= 3

E. 36=4c


For each equation, c = 9 is a solution if it makes the equation true.

To test the each equation, we can follow these steps:

  1. Substitute c = 9 into the equation.
  2. Simplify.
  3. Check if both sides of the equation have the same value.

For example, here's how we could test the first equation:

\begin{gathered}
4-c=5 \\
4-9 \stackrel{?}{=} 5 \\
-5 \neq 5
\end{gathered}

No, c = 9 is not a solution.

 c = 9 is a solution for the following equations:

  • \frac {c}{3} = 3
  • 36=4c