Question

Expand
(2x-5y)^2 using identity

Answer 1

Answer:

$\sf \: Using, \\ \sf(a+b)^2=a^2+b^2+2ab \\ \sf \:=(2xy)^2+(5y)^2+2(2xy)(5y)\\\sf=4x^2y^2+25y^2+20xy^2\\ \sf=y^2(4x^2+25+20x)$