Question

Which ordered pair in the form (x, y) is a solution of this equation?

3x - 4y = 21

A. (-2,-3)
B. (0,7)
C. (7,0)
D. (-3,-2)

Answer 1

Substitute the x and y values from the ordered pairs into the equation, one by one, until both sides of the equation are equal.

Explanation:

A. (-2,-3)

3 * (-2) - 4 * (-3) = 21

-6 + 12 = 21

6 = 21 not equal

B. (0,7)

3 * 0 - 4 * 7 = 21

0 - 28 = 21

- 28 = 21 not equal

C. (7,0)

3 * 7 - 4 * 0 = 21

21 - 0 = 21

21 = 21 equal