Applying parallel line postulate twice
36degree=3x degree +2y degree
126 degrees=12 x degree + 2y degree
So, the two equations are:
3x + 2y = 36
and
12x + 2y = 126
Eliminate x to solve for y
-(3x + 2y)= -(36)
-3x - 2y = -36
Combine the equations
(-3x - 2y)+ (12x + 2y) = (-36) + (126)
-3x -2y + 12x + 2y = -36 + 126
9x = 90
x = 10
Plug value of x back into to the equations to solve for y
3(10) + 2y = 36
30 + 2y = 36
2y =6
y = 3
Optional
Plug x into the other equation to check for error
12(10) +2y = 126
120 + 2y =126
2y = 6
y = 3
