Download Write original equation.

EXAMPLE 1
Solve a two-step equation
Solve x + 5 = 11.
2
x + 5 = 11
2
x + 5 – 5 = 11 – 5
2
x =6
2
2 x =2 6
2
x = 12
Write original equation.
Subtract 5 from each side.
Simplify.
Multiply each side by 2.
Simplify.
ANSWER
The solution is 12. Check by substituting 12 for x in
the original equation.
EXAMPLE 1
CHECK
Solve a two-step equation
x + 5 = 11
2
12 + 5 ?= 11
2
11 = 11
Write original equation.
Substitute 12 for x.
Simplify. Solution checks.
GUIDED PRACTICE
for Example 1
Solve the equation. Check your solution.
1. 5x + 9 = 24
SOLUTION
5x + 9 = 24
5x + 9 – 9 = 24 – 9
5x = 15
5x 15
=
3 3
x=3
Write original equation.
Subtract 9 from each side.
Simplify.
Divide each side by 5
Simplify.
GUIDED PRACTICE
for Example 1
ANSWER
The solution is 3. Check by substituting 3 for x in the
original equation.
CHECK
5x + 9 = 24
?
5 3 + 9 = 24
24 = 24
Write original equation.
Substitute 3 for x.
Simplify. Solution check.
GUIDED PRACTICE
for Example 1
Solve the equation. Check your solution.
2. 4y – 4 = 16
SOLUTION
4y – 4 = 16
4y – 4 + 4 = 16 + 4
4y = 20
4y 20
=
4
4
y=5
Write original equation.
Add 4 to each side
Simplify.
Divide each side by 4.
Simplify.
GUIDED PRACTICE
for Example 1
ANSWER
The solution is 5. Check by substituting 5 for y in the
original equation.
CHECK
4y – 4 = 16
?
4(5) – 4 = 16
16 = 16
Write original equation.
Substitute 5 for y.
Simplify. Solution checks.
GUIDED PRACTICE
for Example 1
Solve the equation. Check your solution.
z
3. – 1 = 3 –7
SOLUTION
–1= z –7
3
–1+7= z –7+7
3
z
6=
3
z
3 6=3
3
18 = z
Write original equation.
Add 7 to each side.
Simplify.
Multiply each side by 3.
Simplify.
GUIDED PRACTICE
for Example 1
ANSWER
The solution is 18. Check by substituting 18 for z in
the original equation.
CHECK
–1= z –7
3
? 18
–1=
–7
3
–1= –1
Write original equation.
Substitute 18 for z.
Simplify. Solution checks.
GUIDED PRACTICE
Solve the equation.
for Example 1
Lesson 3.2, For use with pages 141-146
3. Simplify the expression 3(x + 2) – 4x + 1.
ANSWER
–x + 7
4. There are three times as many goats as sheep in a
petting zoo. Find the number of sheep if the total
number of goats and sheep is 28.
ANSWER
7 sheep