Question

Sam can not read part of this homework problem. -7y +5(3 + ___y) Sam knows the expression simplifies to 3y + 15. What number belongs on the blank line in the homework problem?



A -4


B 4


C 10


D 2

Answer 1

Let the variable A represent the number that goes in the blank.

-7y + 5(3 + Ay) = 3y + 15

-7y + 15 + 5Ay = 3y + 15

-7y + 5Ay = 3y

(-7 + 5A)y = 3y

-7 + 5A = 3

5A = 10

A = 2

Answer: D. 2