Y = -2 x - 9
3 x - 4(-2 x - 9 ) = -8
3 x + 8 x + 36 = - 8
11 x = - 44, x = - 4
y = 8 - 9 , y = -1
This is a unique solution, the system is independent.
If the two angles of the triangle are equal. Well yes, because if the angles are both 50 degrees then the other angle will be 30. but it also depends on the shape of the triangle if they differ.
I am pretty sure the answer is 180
