factorise:5 - 4x(1 + 3x)
5 - 4x(1 + 3x)
= 5 - 4x - 12x2
= 5 - 10x + 6x - 12x2
= 5(1 - 2x)+ 6x (1 - 2x)
= (1 - 2x)(5 + 6x)
