Question

Solve the system equation

x-2y=27
y=5x

A (-4,-20)
B (3,25)
C (-3,-16)
D (-3,-15)​

Answer 1

We will use substitution to solve this system for x.

`x - 2y = 27\\y = 5x\\\\x - 2(5x) = 27\\\\x - 10x = 27\\\\-9x = 27\\\\x = -3`

Now that we know what x is, we can determine y by pluging in -3 for x in one of the original equations. I will use the first one.

`-3 - 2y = 27\\\\-2y = 30\\\\y = -15\\`

We now have our solution.

D.
`(-3, -15)`

We can check our answer by pluging the solution into one of the original equations to see if both sides equal each other. I will use the first equation.

`-3 - 2(-15) = 27\\\\-3 + 30 = 27\\\\27 = 27`

Since the equation checks out, our solution is correct.