Question

I swear if I do not get the answer soon I will have a fluttering panic attack :) 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

Answer 1

this is just a matter of subbing and seeing which ones are true.

3x - 4y = 21

A.) (3,3)...x = 3 and y = 3
now sub
3(3) - 4(3) = 21
9 - 12 = 21
-3 = 21 (incorrect...so this is not a solution)

B.) (1,6)...x = 1 and y = 6
now sub again
3(1) - 4(6) = 21
3 - 24 = 21
-21 = 21 (incorrect...not this one either)

C.) (7,0)...x = 7 and y = 0
3(7) - 4(0) = 21
21 - 0 = 21
21 = 21 (This is correct...this is a solution)

D.) (11,3)...x = 11 and y = 3
3(11) - 4(3) = 21
33 - 12 = 21
21 = 21 (correct...this is also a solution)

So the solutions to the equations are : C and D