Solve the following system of equations using the substitution method.

-y = 5x + 21

-4x + y = 6

Question 1 options:

A)

(3,6)

B)

(3,-6)

C)

(-3,6)

D)

(-3,-6)

D

Step-by-step explanation:

Since we already know what - y is we can use that to find y.

y = - 5x - 21.

Let's substitute that in the bottom equation

-4x - 5x - 21 = 6.

Simplify.

-9x = 27.

x = - 3

Let's solve using

y = - 5x - 21.

to find y.

y = - 5 (-3) - 21

y = 15 - 21

y = - 6.

There you have it!

x = - 3, y = - 6

So ... The correct answer choice is D

I think the answer is D!