Question

25-x^2-4y^2+4xy

 

Answer 1

\(25-x^2-4y^2+4xy=25-\left(x^2-4xy+4y^2\right)=25-\left[x^2-4xy+\left(2y\right)^2\right]=5^2-\left(x-2y\right)^2=\left[5-\left(x-2y\right)\right]\left[5+\left(x-2y\right)\right]=\left(5-x-2y\right)\left(5+x-2y\right)\)

Answer 2

\(=25-\left(x-2y\right)^2=\left(5-x+2y\right)\left(5+x-2y\right)\)