I might be wrong.
I guess that in total all the angles equal to 180, that being said...
m∠BAC = 79
The sum of the left side of these two equations is equal to the same of the right side is these two equations
4x+8y + (-4x+2y) = 20 + 30
10y =50 ( x is eliminated)
y=5
Take this into the second equation
-4x +2y = 30
-4x + 2*5 = 30
x=-5
So x=-5
y=5
Answer:
x = 8 - 3y
Step-by-step explanation:

Hope this helps.
Answer:
x = 18
Step-by-step explanation:
difference between y = 12, x=72 is 6
so if y = 3 then multiply 3×6 = 18