Question

factorise the following
i) x4 - 125 xy3
ii ) a2 + 6a - 7

Answer 1

i) x⁴ - 125xy³

» x(x³ - 125y³)[a³ - b³ = (a - b) (a² + ab + b²)]

» x(x - 5y) (x² + 5xy + 25y²)

ii) a² + 6a - 7

» a² + 7a - a - 7

» a(a + 7) - 1(a + 7)

» (a - 1) (a + 7)