H.C.F. and L.C.M. of Polynomials

Find the H.C.F. and L.C.M. of the following polynomials :
$5x^3{y}^2 \& 10x^2{y}^4$

Find the L.C.M. of the following polynomials :
${(2x-3)}^2(x^2+x-2), 4x^2-x-18 and 2x^2-9x+9$

Find the H.C.F. and L.C.M. of the following polynomials :
$3(x^2+2x-8), 6(x^2+9x+20) and 15(x^2+x-12)$

Find the H.C.F. and L.C.M. of the following polynomials :
$(a^3-b^3){(a+b)}^2, a^4-b^4 and 3a^4+2a^{3}b-5a^2{b}^2$

Find the H.C.F. and L.C.M. of the following polynomials :
$a^2-ab-2b^2 \& a^3-a^{2}b-4a{b}^2+4b^3$

Find the L.C.M. of the following polynomials :
$(x^2-4)(x^2+5x+6), {(x+3)}^2(2x^2+x-6) \& 4x^2-12x+9$

Find the H.C.F. and L.C.M. of the following polynomials :
$2x^2-8 \& 5x^2-20x+20$

Find the L.C.M. of the following polynomials :
$5{(x-y)}^2, 10(x^2-y^2) \& 15{(x+y)}^2$

If the L.C.M. of the following polynomials $4(x^2-y^2), 6(x^3-y^3) \& 9(x^3+y^3)$ is $k\left(x^6-y^6\right)$, then find the value of $k$.

Find the L.C.M. of the following polynomials :
$x^2+2x-15, x^2+9x+20 \& x^2+4x-21$

Find the L.C.M. of the following polynomials :
$6x^2-x-1, 3x^2+7x+2 \& 2x^2+3x-2$

Find the L.C.M. of the following polynomials :
$4x^2{(x+a)}^2, 6a^{2}x(x^2-a^2) \& 9x^3(x^3-a^3)$

Find the L.C.M. of the following polynomials :
$x^3+y^3, {(x+y)}^2 \& x^2-y^2$

Find the L.C.M. of the following polynomials :
$4a^2{x}^2, 2x(x^2-a^2) \& 6a^{3}x(x^3+a^3)$

Find the L.C.M. of the following polynomials :
$x^2+8x+15 \& x^3+10x^2+25x$

Find the L.C.M. of the following polynomials :
$x^2-4x+3 \& x^2-5x+6$

Find the L.C.M. of the following polynomials :
$a^2(a^2-4) \& a^4+2a^2-8a^2$

Find the L.C.M. of the following polynomials :
$x^3-8 \& x^2-5x+6$

Find the L.C.M. of the following polynomials :
${(x+2)}^2{(x+2)}^3(x+3) \& {(x+1)}^3(x+2){(x+3)}^2$

Find the L.C.M. of the following polynomials :
$a^{3}b-a{b}^3 \& a^3{b}^2+a^2{b}^3$