41.8, angle y and the measurement angle labeled as just "138.2" are supplementary angles, meaning that when you add them together they equal 180. So all you have to do is subtract 138.2 from 180 and you get your answer which is 41.8.
2x^3y+18xy-10x^2y-90y
= 2xy(x^2 + 9)- 10y(x^2 + 9)
= (x^2 + 9)(2xy - 10y)
= (x^2 + 9) 2y(x - 5)
= 2y (x^2 + 9) (x - 5)
The answer is -6
So you need to drop the word sum on -6
