Question

Using expansion method solve (10x +5y)(5y +10x)

Answer 1

Please

Answer 2

Just apply the commonly named method of FOIL

(10x +5y)(5y +10x)
= 50xy + 100x^2 + 25y^2 + 50xy
= 100x^2 + 100xy + 25y^2

Being alert, you might have noticed that we have
5(2x+y)(5)(2x+y)
= 25(2x+y)^2
= 25(4x^2 + 4xy + y^2)