Question

Which number should each side of the equation 4/5x=8 be multiplied by to produce he equivalent equation of x=10?

Answer 1

<< Add $.\frac{-4}{5}$ to the left and right of the equation, multiple and make ''opposite multiplation'' to find x.

A) $\frac{4}{5x}. \frac{-4}{5} = 8. \frac{-4}{5}$
$\frac{16}{25x} = \frac{-32}{5}$
25x.(-32)= (-16).5
-800x= -80

**to leave x alone and positive, you must divide to -800.
$x= \frac{-80}{-800}$
$x= \frac{1}{10}$
= INCORRECT

B) $\frac{4}{5x} . \frac{1}{5} = 8. \frac{1}{5}$
$\frac{4}{25x} = \frac{8}{5}$
$25x.8= 4.5$
$200x=20$
$x= \frac{20}{200} = \frac{1}{10}$


C)$\frac{4}{5x} . \frac{5}{4}= \frac{8.5}{4}$
$\frac{1}{x} = \frac{40}{4}$
$\frac{1}{x} =10$
10x=1
$x= \frac{1}{10}$


D) $\frac{4.5}{5x} = 8.5$
$\frac{4}{x} = 40$
40x= 4
x= $\frac{4}{40}$ = 1/10

I think there is a problem with the options :D