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

3a - 4b = 21

A.

(-3, - 2)

B.

(-2, - 3)

C.

(0, 7)

D.

(7, 0)

Answer is D (7, 0)

D. (7,0)

Step-by-step explanation:

Our original equation is 3a-4b=21.

The one we will try first is D. (7, 0)

Since we need to plug it in the form of (a, b) here is the equation now:

3 (7) - 4 (0) = 21

Now we solve:

3*7=21

4*0=0

Now we have 21-0=21

21-0 does equal 21.