Question

20x la a 3-a y - 45x y la a3-a
OFER 90PCTE

Answer 1

$\displaystyle 20x^3y-45xy^3= \\ \\ xy(20x^2-45y^2)= \\ \\ xy(x\sqrt{20}-y\sqrt{45})(x\sqrt{20}+y\sqrt{45})= \\ \\ xy(2x\sqrt5-3y\sqrt5)(2x\sqrt5+3y\sqrt5)= \\ \\ xy[\sqrt5(2x-3y)\sqrt5(2x+3y)]= \\ \\ 5xy(2x-3y)(2x+3y)$