Question

Factorise 5(3a+b)^2 + 6(3a+b) - 8

Answer 1

Let

3a + b = X

$3 {x}^{2} + 6x - 8 \\ 3 {x}^{2} + 6x + 3 - 11 \\ {( \sqrt{3} x + \sqrt{3}) }^{2} - 11 \\ 3 {(x + 1)}^{2} - 11$

on putting X = 3a + b

3( 3a + b)^2 - (sqrt11)^2

(sqrt3((3a + b) - sqrt11)(sqrt3(3a + b) + sqrt11)

Answer 2

Answer:

$\huge\mathbb\red{Answer:}$

Let (3a+b)=Y.

$5y {}^{2} - 6y - 8 \\ = 5y {}^{2} - 10y + 4y - 8 \\ = 5y(y - 2) + 4(y - 2) \\ = (5y + 4)(y - 2) \\ = 5 \times (3a + b) + 4(3a + b - 2) \\ = (15a + 5b + 4)(3a + b - 2)$

Hope it helps you ❤❤❤