Page 150 - Algebra 1

Example
2
Solving Two-Step Equations with Positive Coefficients
Solve the equation. Then check the solution.
4x + 5 = 17
SOLUTION To isolate x, first eliminate 5 and then eliminate the 4. 4x + 5 = 17
Math Reasoning
Write Explain why the first step in checking the solution is to multiply
by 4 and the last step in solving the equation is to divide by 4.
-__5 = -__5
4x = 12
4x = 12 __
44 x=3
Subtraction Property of Equality Simplify.
Division Property of Equality
Check Substitute3forxintheoriginalequation.
4(3) + 5 17 12 + 5 17
17=17 ✓
Solving Two-Step Equations with Negative
Coefficients
Solve the equation. Then check the solution.
8 = -5m + 6
SOLUTION To isolate m, first eliminate the 6 and then eliminate the -5.
Example
3
8 =
-__6 =
2 =
_2 = -5
-_2 = 5
-5m + 6 -__6
-5m _-5 m
-5 m
Subtraction Property of Equality Simplify.
Division Property of Equality
Simplify.
Check Substitute-_2 form. 5
8 - 5 ( - _2 ) + 6 5
8 2+6 8=8 ✓
Lesson 23 135