Question

$x^{2} - b^{2} -ax-ab$
$a^{2} y^{2} - x^{6}$
$c^{2} -6c+9-4x^{2}$
$4 c^{2} +20c+25-9 a^{2}$
$y^{2} x+y+y x^{2} +x+4yx+4$
$c^{2} -4c+4-9 x^{2}$
$3 x^{2} +2x-xy-2 y^{2} +y ^{3} -3xy ^{2}$
$x^{2} +x-xy- y^{2} +y ^{3} -xy^{2}$
$a^{2} x+a+a x^{2} +x+2ax+2$