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Solving Two-Step Equations
- A two-step equation has two operations. You will need to cancel or undo each one by using its inverse operation.
- Addition and subtraction are inverse operations. You can use the Addition Property of Equality and the Subtraction Property of Equality to undo the opposite operation.
- Multiplication and division are inverse operations. You can use the Multiplication Property of Equality and the Division Property of Equality to undo the opposite operation.
- Remember to work backwards from the order of operations. Undo addition and subtraction first, then multiplication and division.
Solving Two-Step Equations
4x − 3 = 81
- 4x = 81 + 3
- 4x = 84
- x = [84/4]
x = 21
45 = [x/3] + 17
- 45 − 17 = [x/3]
- 28 = [x/3]
84 = x
11 + 8y = 59
- 8y = 59 − 11
- 8y = 48
- y = [48/8]
y = 6
13x + 4 = 43
- 13x = 43 − 4
- 13x = 39
- 4x = [39/13]
x = 3
− 2m − 63 = 47
- − 2m = 47 + 63
- − 2m = 110
- m = [110/( − 2)]
m = − 55
− 5 = − 19 − [t/7]
- − 5 + 19 = − [t/9]
- 14 = − [t/9]
- 14 ×9 = − t
- 126 = − t
t = − 126
Duy begins with 16 gallons of gas in his car. His car uses 3 gallons of gas per hour of driving. He will stop to get more gas when there is 1 gallon left in the tank. After how many hours will Duy need to stop to refuel?
- Let t = how long Duy drives
- 16 gallons − (3 gallons per hour)t = 1 gallon
- − 3t = 1 − 16
- − 3t = − 15
t = 5 hours
A phone plan costs $ 0.45 per call and $ 0.10 per minute. You pay $ 2.30 for the call. Write and solve an equation to find the length of the call.
- Let m = the length of the call.
- $ 2.30 = $ 0.45 + $ 0.10m
- $ 2.30 − $ 0.45 = $ 0.10m
- $ 1.85 = $ 0.10m
- m = $ 1.85 ÷$ 0.10
m = 18.5 minutes
You go to a county fair. It costs $ 11 to enter the fair, and it costs $ 3 for each ride at the fair. You spend $ 26 at the fair. How many rides did you ride?
- Let r = number of rides you rode
- $ 26 = $ 11 + $ 3r
- $ 26 − $ 11 = $ 3r
- $ 15 = $ 3r
- r = $ 15 ÷$ 3
r = 5 rides
Eric buys one sandwich for $ 5.30 and 5 drinks. The total cost is $ 19.05. How much does one drink cost?
- Let d = cost of one drink.
- $ 5.30 + 5d = $ 19.05
- 5d = $ 19.05 − $ 5.30
- 5d = $ 13.75
- d = $ 13.75 ÷5
d = $ 2.75
*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.
Answer
Solving Two-Step Equations
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