Which ordered pairs in the form (x, y) are solutions to the equation 3x – 4y = 21?
choose all answers that are correct
a. (−3, 3)
b. (−1, −6)
c. (7, 0)
d. (11, 3)

One way of knowing the correct answers, we substitute the ordered pairs to the function and see whether it would make the function true. 

3x – 4y = 21

A. (−3, 3)
3(-3) – 4(3) = 21
-21 = 21 > not equal

B. (−1, −6)
3(-1) – 4(-6) = 21
21 = 21 > equal

C. (7, 0)
3(7) – 4(0) = 21
21 = 21 > equal

D. (11, 3)
3(11) – 4(3) = 21
21 = 21 > equal