Question

Find the square: (5x - 4y)2

(and please put the process of solving the equation)

Answer 1

$(5x-4y)^2$
$(5x-4y)(5x-4y)$

Multiply each term in one bracket in turn by the terms in the other bracket

$(5x)(5x) = 25x^2$
$(5x)(-4y)=-20xy$
$(-4y)(5x)=-20xy$
$(-4y)(-4y)=16y^2$

Put them together we have
$25x^2-20xy-20xy-16y^2$
$25x^2-40xy-16y^2$