Question

tim x 

(2 x/5-1): -5 = 1/7

lam on giup minh 1 ph nua mih phai nop roi

Answer 1

(2x/5-1) : -5 = 1/7

<=> 2x/4 : -5/1 = 1/7

<=> 2x/4 = 1/7 . -5/1

<=>2x/4 = -5/7

<=>-5.4=2x.7

<=>-20=2x.7

<=> 2x=-20/7

<=> x=-10/7

Answer 2

Giải : 

\((\frac{2x}{5}-1):\left(-5\right)=\frac{1}{7}\)

\(\frac{2x}{5}-1=\frac{1}{7}\cdot\left(-5\right)\)

\(\frac{2x}{5}-1=\frac{-5}{7}\)

\(\frac{2x}{5}=\frac{-5}{7}+1\)

\(\frac{2x}{5}=\frac{2}{7}\)

\(\Rightarrow2x\cdot7=2\cdot5\)

\(2x\cdot7=10\)

\(2x=\frac{10}{7}\)

\(x=\frac{10}{7}:2\)

\(x=\frac{10}{7}\cdot\frac{1}{2}\)

\(x=\frac{10}{14}=\frac{5}{7}\)