Question

If $\left(\frac{\frac{x}{4}-\frac{3}{5}}{\frac{4}{3}-7x}\right)=-\frac{3}{20}$, what will be the value of $30x$ ?

Answer 1

$\left(\frac{\frac{x}{4}-\frac{3}{5}}{\frac{4}{3}-7x}\right)=\frac{-3}{20}$

$\Rightarrow \frac{\frac{5x-12}{20}}{\frac{4-21x}{3}}=\left(\frac{-3}{20}\right)$

$\Rightarrow \left(\frac{5x-12}{4-21x}\right)\times \left(\frac{3}{20}\right)=\left(\frac{-3}{20}\right)$

$\Rightarrow \left(\frac{5x-12}{4-21x}\right)=-1$

$\Rightarrow (5x-12)=-(4-21x)$

$\Rightarrow 5x-12=-4+21x$

$\Rightarrow -12+4=21x-5x$

$\Rightarrow -8=16x$

$\therefore x=-\left(\frac{1}{2}\right)$

$\Rightarrow 30x=30\times \frac{-1}{2}$

$\therefore 30x=\left(-15\right)$