Question

diferencia de cuadrados de (a-b)²-(c+d)²

Answer 1

(a-b)²-(c+d)²    
se aplica
 $x^2-y^2=\left(x+y\right)\left(x-y\right)$
$=\left(\left(a-b\right)+\left(c+d\right)\right)\left(\left(a-b\right)-\left(c+d\right)\right)$
desarrollando los parentesis
 $=\left(a+c+d-b\right)\left(a-b-c-d\right)$