$\frac{1}{7}$+$\frac{6}{7}$ × $(x-1\frac{3}{4})=4$
$\frac{6}{7}$ × $(x-1\frac{3}{4})=4-\frac{1}{7}$
$\frac{6}{7}$ × $(x-1\frac{3}{4})=\frac{27}{7}$
$(x-1\frac{3}{4})=\frac{27}{7} :\frac{6}{7}$
$(x-1\frac{3}{4})=\frac{27}{7} ×\frac{7}{6}$
$x-\frac{7}{4}=\frac{9}{2}$
$x=\frac{9}{2}+\frac{7}{4}$
$x=\frac{18}{4}+\frac{7}{4}$
$x=\frac{25}{4}$
Vậy $x=\frac{25}{4}$