Factorise the following quadratic polynomials by splitting the middle term

$15 x^{2}+7 x-2$

Factorise

$9 x^{2}-21 x y+10 y^{2}$

Expand

$(2 x-3)(2 x+5)$

Find the quotient and the remainder when $x^{3}+x^{2}-10 x+8$ is divided by

$x-1$

Factorise the following quadratic polynomials by splitting the middle term

$x^{2}-12 x+20$