Ok, corresponding angles are in the same position on the two parallel lines cut by the transversal. And they are equal in measure. So, upper right = upper right.
So A = B
4x = -5(x -18)
4x = -5x + 90
9x = 90
x = 10
Angle A = 4x = 40 degrees, which means angle B is also 40, but let's show the work: