Question

Using the identity $(x+a)(x+b)=x^2+(a+b)x+ab$, find out the following products:
$(2+x)(2-y)$

Answer 1

$(2+x)(2-y)$

using, $(x+a)(a+b)=x^2+(a+b)x+ab$

$\Rightarrow (2+x)(2-y)=2^2+(x-y)2-\left(xy\right)$

$=4+2x-2y-xy.$

Hence, the answer is $4+2x-2y-xy.$