Which ordered pairs in the form (x, y) are solutions to the equation 3x−4y=21? Select each correct answer.

1. (7, 0)

2. (11, 3)

3. (−3, 3)

4. (−1, −6)

We must plugin values:
3(7)-4(0)=21, is CORRECT since 7•3 is 21 and -4•0 is 0
3(11)-4(3)=21 is CORRECT since 3•11=33 and -4•3=-12 so 33-12=21
3(-3)-4(3)=21 is INCORRECT since 3•-3 is -9 and -4•3 is -12, -9-12 is -21
3(-1)-4(-6)=21 is CORRECT since 3•-1 is -3 and -4•-6 is 24 and so 24-3=21