Cho 1/7 + 6/7 x (x – 1 3/4)=4. Vậy giá trị của x là:

$\frac{1}{7}$+$\frac{6}{7}$ × $(x-1\frac{3}{4})=4$

$\frac{6}{7}$ × $(x-1\frac{3}{4})=4-\frac{1}{7}$

$\frac{6}{7}$ × $(x-1\frac{3}{4})=\frac{27}{7}$

$(x-1\frac{3}{4})=\frac{27}{7} :\frac{6}{7}$

$(x-1\frac{3}{4})=\frac{27}{7} ×\frac{7}{6}$

$x-\frac{7}{4}=\frac{9}{2}$

$x=\frac{9}{2}+\frac{7}{4}$

$x=\frac{18}{4}+\frac{7}{4}$

$x=\frac{25}{4}$

Vậy $x=\frac{25}{4}$