Question 1056647
Trust what you learned about fractions, regardless if with variable expressions or plainly written real numbers.


{{{(-3x)/(5x-20)=v/(40-10x)}}}, and you want to know v.


{{{((-3x)/(5x-20))(40-10x)=v}}}


{{{v=(-3x)(40-10x)/(5x-20)}}}


{{{v=(-3x)(10(4-x))/(5(x-4))}}}
The negative factor,...


{{{v=(-1)(3x)(10(4-x))/(5(x-4))}}}


{{{v=(-1)(3x)(2(4-x))/(x-4)}}}


{{{v=3x(2(x-4))/(x-4)}}}


{{{v=3x*2}}}


{{{v=6x}}}