Question

  

Answer 1

4: \(=4-\left(x^2-2xy+y^2\right)\)

\(=4-\left(x-y\right)^2\)

\(=\left(2-x+y\right)\left(2+x-y\right)\)

5: \(=\left(9x^2-1\right)+3y\left(3x+1\right)\)

\(=\left(3x-1\right)\left(3x+1\right)+3y\left(3x+1\right)\)

\(=\left(3x+1\right)\left(3x-1+3y\right)\)

Answer 2

4) \(4-x^2+2xy-y^2\)

\(=4-\left(x-y\right)^2\)

\(=\left(4-x+y\right)\left(4+x-y\right)\)

5) \(9x^2-1+9xy+3y\)

\(=\left(3x-1\right)\left(3x+1\right)+3y\left(3x+1\right)\)

\(=\left(3x+1\right)\left(3x+3y-1\right)\)