Subtract (x+109) from 180; the result is 71-x. The reason for doing this is that we want to equate "corresponding angles." 71-x and x+89 are corresponding angles. Set them = to one another and then solve the resulting equation for x:
71-x = x+89
-18 = 2x, so x = -9
Now let's determine the angle x+89. Since x=-9, that angle is 80 (degrees).