Question

Solve the quadratic equation by factorisation method:

x² – 15x + 54 = 0

Solve the following quadratic equation by the factorisation method:

x² – 15x + 54 = 0

Answer 1

x² − 15x + 54 = 0

∴ x² − 9x − 6x + 54 = 0

∴ x(x − 9) − 6(x − 9) = 0   ....`[(54 = − 9 − 6),(−9 xx −6 = + 54),(−9 −6 = −15)]`

∴ (x − 9)(x − 6) = 0

If the product of two numbers is zero, then at least one of the two numbers is zero.

x − 9 = 0 or x − 6 = 0

∴ x = 9 or x = 6 

∴ The roots of the given quadratic equation are 9 and 6.