Question

Which of the following equations does the graph below represent?

A. 3x + 7y = 21

B. -3x + 7y = 21

C. x + 7y = 21

D. -3x + y = 21

Answer 1

B

Explanation:

if x = 0 ; y = 3

if x = -7 ; y = 0

A 0 + 7(3) = 21

0 + 21 = 21

21 = 21 (ok)

3(-7) + 0 = 21

-21 = 21 (false)

B

0 + 21 = 21

21 = 21 (ok)

(-3)(-7) + 0 = 21

21 = 21 (ok)