How do I solve this equation?

Question

How do you solve the system by substitution 

 

y=-6x-16

-3x-y=10

 

 

please help how to solve

Answer 1

Step One: State our two equations (Eq)

Eq 1 is y=-6x-16
Eq 2 is -3x-y=10

Step Two: Substitute y into Eq 2 

-3x-(-6x-16)=10 Distribute

-3x+6x+16=10 Combine Like Terms

3x=-6 Divide both sides by 3

x=-2

∴x=-2 while y=-4

BONUS: How can we check our answer?

Let's substitute our x=-2 value into Eq 1.

y=-6(-2)-16

y=12-16

y=-4

Plug this into the other equation to fond y

-3x+4=10 Subtract 4 from both sides 

-3x=6 Divide both sides by 3

x=-2