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Main Idea and New Vocabulary
NGSSS
Example 1:Solve a Two-Step Equation
Example 2:Solve Two-Step Equations
Example 3:Solve Two-Step Equations
Example 4:Solve Two-Step Equations
Key Concept:Solving Two-Step Equations
Example 5:Real-World Example: Solve Two-Step Equations
Five-Minute Check
MA.7.A.3.3 Formulate and use different strategies to solve one-step and two-step linear equations, including equations with rational coefficients.
Also addresses MA.7.A.3.2.
Solve a Two-Step Equation
Solve 4x + 3 = 19. Check your solution.
4x + 3 = 19 Write the equation.
– 3 = – 3 Undo the addition first by subtracting 3 from each side. 4x = 16
x = 4 Simplify.
Division Property of Equality
Answer: The solution is 4.
Solve a Two-Step Equation
4x + 3 = 19 Write the original equation.
19 = 19 The sentence is true.
Check
4(4) + 3 = 19 Replace x with 4.
?
Solve 6 + 5y = 26. Check your solution.
Solve Two-Step Equations
6 + 5y = 26 Write the equation.
– 6 = – 6 Undo the addition first by subtracting 6 from each side. 5y = 20
y = 4 Simplify.
Division Property of Equality
Answer: The solution is 4.
Solve Two-Step Equations
6 + 5y = 26 Write the original equation.
26 = 26 The sentence is true.
Check
6 + 5(4) = 26 Replace y with 4.
?
Solve Two-Step Equations
Solve −3c + 9 = 3. Check your solution.
–3c + 9 = 3 Write the equation.
– 9 = – 9 Undo the addition first by subtracting 9 from each side. –3c = –6
c = 2 Simplify.
Division Property of Equality
Answer: The solution is 2.
Solve Two-Step Equations
–3c + 9 = 3 Write the original equation.
3 = 3 The sentence is true.
Check
–3(2) + 9 = 3 Replace c with 2.
?
Solve Two-Step Equations
Solve Check your solution.
– 6 = – 6 Undo the addition first by subtracting 6 from each side.
–18 = t Simplify.
–6 = t13
Multiplication Property ofEquality
(3)(–6) = (3) t13
Write the equation.
Answer: The solution is –18.
Solve Two-Step Equations
Write the original equation.
0 = 0 The sentence is true.
Check
? Replace t with –18. 0 = 6 + (–18)13
FINANCIAL LITERACY Luis’s cell phone plan costs $39 per month. Text messages cost an additional $0.15 each. If Luis’s cell phone bill last month totaled $55.05, how many text messages did he send?
Solve Two-Step Equations
Solve Two-Step Equations
Solve Two-Step Equations
39 + 0.15t = 55.05 Write the equation.
– 39 = – 39 Subtract 39 from each side.
t = 107 Simplify.
Division Property of Equality
Answer: Luis sent 107 text messages.
Solve Two-Step Equations
39 + 0.15t = 55.05 Write the original equation.
Check
?39 + 0.15(107) = 55.05 Replace t with 107.
39 + 16.05 = 55.05?
39 + 16.05 = 55.05
TENNIS Shannon’s tennis club membership costs $20.00 per month. In addition, she pays $8.00 for court rental every time she plays. If her bill for this month was $52.00, how many times did she play tennis?
A. 24 times
B. 9 times
C. 4 times
D. 3 times
Solve 4x + 8 = 32.
A. 6
B. 10
C. 20
D. 96
Solve 15 – 3a = 45.
A. –10
B. 10
C. 20
D. 90
Solve –9 + 7x = 68.
A. 70
B. 52
C. 11
D.
Solve –18 = –2m –68.
A. 52
B. 43
C. 25
D. –25
Four less than six times a number is 32. Find the number.
A. 22
B. 6
C. –6
D.
Daryl can cut 3 lawns in an hour. How many hours will it take him to cut 27 lawns?
A. 30 hours
B. 24 hours
C. 15 hours
D. 9 hours