Question 861082
3x^2 -48y^2/ 20a^-3b^-2c^5 means {{{3x^2 -48y^2/ 20a^-3b^-2c^5}}} ,
10a^2b^4c^-3/ x^2+xy - 12y^2 means {{{10a^2b^4c^-3/ x^2+xy - 12y^2}}}and that x in the middle was confusing.
 
I guess that you want the product of
(3x^2 -48y^2)/( 20a^-3b^-2c^5) ={{{(3x^2 -48y^2)/( 20a^-3b^-2c^5)}}}
times (10a^2b^4c^-3)/( x^2+xy - 12y^2) ={{{(10a^2b^4c^-3)/( x^2+xy - 12y^2)}}} .
 
{{{((3x^2 -48y^2)/( 20a^-3b^-2c^5))*((10a^2b^4c^-3)/( x^2+xy - 12y^2))=(3x^2 -48y^2)(10a^2b^4c^-3)/(( 20a^-3b^-2c^5)(x^2+xy - 12y^2))}}}
={{{3(x^2-16y^2)(10a^2b^4c^-3)/(( 20a^-3b^-2c^5)(x+4y)(x-3y))=3(x+4y)(x-4y)(10a^2b^4c^-3)/(( 20a^-3b^-2c^5)(x+4y)(x-3y))}}}
={{{(x+4y)*(x-4y)*3*10*a^2*b^4*c^-3/((x+4y)*(x-3y)* 20*a^-3*b^-2*c^5)= ((x+4y)/(x+4y))*((x-4y)/(x-3y))*(3*10/20)*(a^2/a^-3)*(b^4/b^-2)*(c^-3/c^5)}}}
={{{1*((x-4y)/(x-3y))*(3/2)*a^((2-(-3)))*b^((4-(-2)))*c^((-3-5))=((x-4y)/(x-3y))*(3/2)*a^5*b^6*c^(-8)=(3/2)*a^5*b^6*(1/c^8)*((x-4y)/(x-3y))}}}
={{{3a^5b^6(x-4y)/(2c^8(x-3y))}}}