Question

factorise (a-3b)² - 9(a-3b) +20​

Answer 1

$(a - 3 {b)}^{2} - 9(a - 3b) + 20 \\ ( {a}^{2} + {(3b)}^{2} - 2 \times a \times 3b) - 9a + \\ 27b + 20 \\ \\ {a}^{2} + 9 {b}^{2} - 6ab - 9a + 27b + 20$

Answer 2

Step-by-step explanation:

let a-3b = X

then x²-9x+20

or x²-5x -4x +20

or x(x-5) --4(x-5)

or (a-3b-5)(a-3b-4)