Question

a)       5x^2-20

b)x^2-20x+100-4y^2

 

Answer 1

b) \(x^2-20x+100-4y^2\)

\(=\left(x^2-20x+100\right)-4y^2\)

\(=\left(x-10\right)^2-\left(2y\right)^2\)

\(=\left(x-10-2y\right)\left(x-10+2y\right)\)

\(=\left(x-2y-10\right)\left(x+2y-10\right)\)

Answer 2

a) \(5x^2-20=5\left(x^2-4\right)=5\left(x-2\right)\left(x+2\right)\)

Answer 3

\(5x^2-20\\ =5\left(x^2-4\right)\\ =5\left(x-2\right)\left(x+2\right)\)

\(x^2-20x+100-4y^2\\ =\left(x-10\right)^2-\left(2y\right)^2\\ =\left(x-10-2y\right)\left(x-10+2y\right)\)