Factor quadratic trinomials 27x^2-90x+27

27x^2-81x-9x+27 In this case, just in your mind multiply 27 (coefficient of x^2) by the constant value 27 (the end value of the quadratic trinomial). Then find factors that give you the value - 90 when you add and 729 (27*27) when you multiply.

Factorise the values

27x (x-3) - 9 (x-3)

Which will give you

(27x-9) (x-3)