Question

Expand:
(2x-5y)^2

Answer 1

4 x^2-20 x y+25 y^2

Answer 2

\[(x-y)^2=x^2-2xy+y^2\]
\[(2x-5y)^2=(2x)^2-2(2x)(5y)+(5y)^2\]
\[=4x^2-20xy+25y^2\]