LESSON

How do you write a two-step equation?

Writing Two-Step Equations8.1

Texas Essential Knowledge and Skills

The student is expected to:

Expressions, equations, and relationships —7.10.A

Write one-variable, two-step equations and inequalities to represent constraints or conditions within problems.

Expressions, equations, and relationships—7.10.CWrite a corresponding real-world problem given a one-variable, two-step equation or inequality.

Expressions, equations, and relationships—7.11.A

Model and solve one-variable, two-step equations and inequalities.

Mathematical Processes

7.1.B

Use a problem-solving model that incorporates analyzing given information, formulating a plan or strategy, determining a solution, justifying the solution, and evaluating the problem-solving process and the reasonableness of the solution.

Texas Essential Knowledge and Skills

The student is expected to:

ADDITIONAL EXAMPLE 1

A taxi driver charges $3.25 for the first mile of the trip and $1.25 for each mile after that. He charges a customer $17 for a ride. Write an equation that would help the customer find the distance she traveled in the taxi.3.25 + 1.25x = 17

ADDITIONAL EXAMPLE 2

Write a corresponding real-world problem to represent 80 – 3x = 53.Sample answer: Kendall had $80 in her bank account. After she bought 3 shirts that each cost the same amount, she has $53 in her account. How much did each shirt cost?

8.1 LESSON QUIZ

Joaquin is ordering 5 identical sandwiches anda bag of chips. The bag of chips costs $1.25, and the entire order costs $38.75. Write an equation you can use to find the price of a sandwich.

7.10.A, 7.10.C

1.

5s + 1.25 = 38.75

The drama club is planning a field trip.Two-thirds of the drama club will attend, in addition to 8 teachers. There are 48 people going on the field trip. Write an equation you can use to find the number of students in the drama club.

2.

d + 8 = 48

Write a real-world problem that corresponds to the equation 200 – 7x = 95.

3.

Sample answer: Rico made 200 cupcakes.He gave the same number of cupcakes to each of his 7 friends. When he was finished, he had 95 cupcakes left. How many cupcakes did he give to each friend?

Write a real-world problem that corresponds to the equation 10x + 30 = 100.

4.

Sample answer: Baxter runs 10 times in a month. Each time he runs the same distance. Ashley runs 30 miles in the same month. Together, they ran 100 miles. How many miles did Baxter travel each time he went running?

Yvette is starting a jewelry business. She spends $120 on supplies and makes 18 necklaces. She wants to earn a profit equal to 3 times the amount she spent on supplies. Use this information to write 3 different equations that Yvette could use to determine how much she should charge for each necklace.

Possible answer:18n = 360 + 12018n – 120 = 36018n – 360 = 120

How do you write a two-step equation?

Sample answer:Choose a variable for the unknown value you are trying to find. Use important words from the problem to identify the correct operations and numbers to use.