Question

Ahhhh i need help again.

Which two expressions are equivalent?

A. 7(3 + x) and 7∙ 3 + 3 ∙ x
B. 7 + 3 + x and (7 + 3) + x
C. 7 ∙ x ∙ 3 and 7(x + 3)
D. 7 ÷ (3 – x) and 7 ÷ (x – 3)

Answer 1

B

Explanation:

A. these simply to 21 + 7x and 21 + 3x

• this one is incorrect because the 7x and 3x are different

B. these simplify to 10 + x and 10 + x

• this is the correct one since they are exactly the same

C. these simplify to 21x and 7x + 21

• these two are not the same because one expression has only a number with a variable but the other one has a number with a variable and another number

D. these simplify to
`(7)/(3-x)` and
`(7)/(x-3)`

• in subtraction, the order of the 3 and the x matters, so the equations are not the same
• example: 6 - 4 = 2 but 4 - 6 = -2