Question

Solve the following quadratic equation by factorisation.

x² – 15x + 54 = 0

Answer 1

x² – 15x + 54 = 0 

Two numbers that multiply to 54 and add to −15. These are −9 and −6.

x² − 9x − 6x + 54 = 0

x(x − 9) − 6(x − 9) = 0

(x − 6)(x − 9) = 0

x − 6 = 0 or x − 9 = 0

x = 6 or x = 9

So, 6 and 9 are the roots of the given quadratic equation.