Question

Answer 1

(x+y-x+y)(x+y+x-y)

 

Answer 2

\(11,\left(x+y\right)^2-\left(x-y\right)^2=\left(x+y-x+y\right)\left(x+y+x-y\right)=2y.2x=4xy\\ 18,x^2-5x+4=\left(x^2-4x\right)-\left(x-4\right)=x\left(x-4\right)-\left(x-4\right)=\left(x-1\right)\left(x-4\right)\)

Answer 3

11. = (x² +2xy +y² ) - (x² -2xy +y²)

= x² +2xy +y² -x² +2xy -y² 

= 4xy

12.= x² -4x - x+4 

= x.(x-4) -(x-4)

= (x-1)(x-4)