Page 26 - Math Course 2 (Book 1)

Solving Algebraic Equations

To check your solution, replace x with –8 in the Solve Equations by Dividing
original equation.

Check Example
7x = –56 Write the equation.
? y
7(-8) = –56 Check to see whether Solve . Check your solution and graph it
= –12
this statement is true. –5
on a number line.
–56 = –56 The statement is true.
y = –12 Write the equation.
–5
Answer The solution is –8.
y Multiply each side by –5
7
–5 (–5) = –12 (–5) to undo the division in –5
–10 –8 –6 –4 y = 60 Simplify.

Check
REAL WORLD EXAMPLE y = –12 Write the equation.
–5
? Check to see whether
HOBBIES 60 = –12 this statement is true.
Esteban spent $112 on boxes of baseball cards. If –5
he paid $14 per box, how many boxes of cards did –12 = –12 The statement is true.
Esteban buy?

Words $14 times the total number of boxes The solution is 60. To graph it,
equals the total. Answer draw a dot at 60 on a number
line.

Variable Let x represent the number of boxes.
30 40 50 60 70 80 90 100
Equation $14 • x = $112

Your Turn!
Solve the equation.

14 x = 122 Write the equation. Solve Equations by Dividing
14x = 122 Divide each side by 14. Solve 4x = –12. Check your solution
14 14
A. –48
x = 8 Simplify.
B. –3
C. 3
D. 48
To check your solution, replace x with 8 in the
original equation.

Check Answer
14x = 112 Write the equation.

14(8) = 112 Check to see whether this
statement is true.

112 =112 The statement is true.

Therefore, Esteban bought 8
Answer
boxes of cards.

18