Question

Solve 14−2x=28 using the replacement set {−21, −7, 7} .

A. −21
B. −7
C. 7
D. I don't know.

Answer 1

Answer: the answerd is B

explanation: i take the Test A in k12

Answer 2

B

Explanation:

substitute the values from the replacement set into the left side of the equation to find which values of x make it true.

x = - 21

14 - 2(- 21) = 14 + 42 = 56 ≠ 28 ← False

x = - 7

14 - 2(- 7) = 14 + 14 = 28 ← True

x = 7

14 - 2(7) = 14 - 14 = 0 ≠ 28 ← False

Thus x = - 7 is the solution