Question

a)7x²+14xy

b)3(x+4)-x²-4x

c)x²-2xy+y²-z²

d)x²-2x-15

Answer 1

\(b,3\left(x+4\right)-x^2-4x=3\left(x+4\right)-\left(x^2+4x\right)=3\left(x=4\right)-x\left(x+4\right)=\left(x+4\right)\left(3-x\right)\)

\(d,x^2-2x-15=x^2-5x+3x-15=\left(x^2-5x\right)+\left(3x-15\right)=x\left(x-5\right)+3\left(x-5\right)=\left(x-5\right)\left(x+3\right)\)

Answer 2

b) 3(x + 4) - x² - 4x

= 3(x + 4) - (x² + 4x)

= 3(x + 4) - x(x + 4)

= (x + 4)(3 - x)

d) x² - 2x - 15

= x² - 5x + 3x - 15

= (x² - 5x) + (3x - 15)

= x(x - 5) + 3(x - 5)

= (x - 5)(x + 3)