a)x^2+2x
we can factorise this by x
x(x+2)
b)2x^2-6x
we can factorise this by 2x
2x(x-3)
c)15x-10x^3
we can factorise this by 5x
5x(3-2x^2)
d)9x^2+3x^3
this can be factorised by 3x^2
3x^2(3+x)
