Question 1160798
{{{(7x-13)/(4-3x)}}} have to be multiplied by to end up with a denominator in the rational expressions of {{{20x^2-15x^3}}}?

{{{20x^2-15x^3}}}
{{{5x^2(4-3x)}}}=>{{{(7x-13)/(4-3x)}}} have to be multiplied by {{{5x^2}}}

If the rational expression {{{(4x^2-2x)/(4x^2+20x) }}} can be simplified to {{{(2x-1)/(2x+10)}}} what are the restrictions on the original rational expression?

{{{(4x^2-2x)/(4x^2+20x) }}}......in both numerator and denominator factor out {{{2x}}}

{{{2x(2x-1)/2x(2x+10) }}}.........simplify

{{{cross(2x)(2x-1)/cross(2x)(2x+10) }}}

so, both numerator and denominator  the rational expression {{{(4x^2-2x)/(4x^2+20x) }}} factor out common {{{2x}}} to simplify to{{{ (2x-1)/(2x+10)}}}