Please factor the problem completely

5x 4th power y --80x square y

5x⁴y - 80x²y
——————————factor out the 5
5(x⁴y - 16x²y)
——————————factor out the x²
5x²(x²y - 16y)
——————————factor out the y
5x²y (x² - 16)
——————————notice that (x² - 16) is a difference of squares. Factor that out.
5x²y (x+ 4)(x - 4)

I hope this helps!

5x^2y(x^2-16) =
5x^2y(x+4)(x-4)