Question

A student says that if 5x2 = 20, then x must be

Answer 1

Answer:

I agree with the student's answer. "x" cannot be -2 because then it would make -20 which is not equal to 20:

5(-2)(2) = ?

-10 x 2 = ?

? = -20

-20 ≠ 20

Step-by-step explanation:

Justificaiton:

5(x)(2) = 20

10(x) = 20

10/10(x) = 20/10

x = 2

Second Justification:

5(x)(2) = 20

5/5(x)(2) = 20/5

2x = 4

2x/2 = 4/2

x = 2