Lesson 13-3 Check Your Understanding ACTIVITY 13

Lesson 13-3
Modeling and Solving Subtraction Equations
ACTIVITY 13
continued
My Notes
Check Your Understanding
5. Enzo still owes $750 on his new furniture. He has already paid $600
on it. What was the original cost of the furniture? Define a variable
and write a verbal model and equation for this situation. Then solve
the equation and check the solution.
6. Yusra’s dog is overweight. The vet says the dog needs to lose
7 pounds to get down to the desirable weight of 45 pounds. How
much does Yusra’s dog weigh? Define a variable and write a verbal
model and equation for this situation. Then solve the equation and
check the solution.
LESSON 13-3 PRACTICE
8. Model with mathematics. Payat put $420 from his savings
account into a certificate of deposit to earn more interest. He then
had $80 left in his savings account. How much did Payat have in his
savings account before he opened the certificate? Define a variable
and write a verbal model and equation for this situation. Then solve
the equation and check the solution.
9. Critique the reasoning of others. Marsha said she could solve
x − 3 = 7 using the balance scale method by adding 3 to each side of
the scale. Do you think her reasoning is correct? Explain.
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Unit 3 • Expressions and Equations
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7. You see a coat on sale for $78. The sign says that the price is $15 off
the original price. What was the original price? Define a variable and
write a verbal model and equation for this situation. Then solve the
equation and check the solution.