Which of the following ordered pairs represents the solution to the system given below?

x − 3y = 12
2x + 6y = 60

(0, −4)
(12, 0)
(3, 21)
(21, 3)

Question

Which of the following ordered pairs represents the solution to the system given below?

x − 3y = 12
2x + 6y = 60

 (0, −4)
(12, 0)
(3, 21)
(21, 3)

nottim · Answer

rearrange one of the equations to solve for y or x, and then sub it into another.

anonymous · Answer

So take the first equation and make it $$-3y = -x + 12$$

anonymous · Answer

Which is $$-y = \frac{ -x }{ -3} - 4$$

anonymous · Answer

i meant y not -y

anonymous · Answer

y = $$1/3x -4$$

anonymous · Answer

so then take that and plug it in to 2x + 6y = 60
$$2x + 6(1/3x−4) = 60$$ and then simplify

nottim · Answer

Agh, don't tell them the answer.

anonymous · Answer

I didn't...

nathaliama13 · Answer

@NotTim @Jackmullen10 do I use the substitution method.

nottim · Answer

Yes. Definitely. that's what he and I said.