$${{\mathtt{7}}}^{{\mathtt{x}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{7}}}^{\left({\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{2}}\right)}{\mathtt{\,\small\textbf+\,}}{\mathtt{7}}{\mathtt{\,\times\,}}\left({\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\right) = {\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{393}}$$
If the original problem were entered slightly incorrectly:
7x + 7(x - 2) + 7(x + 1) = 7·393
7x + 7x · 7-2 + 7x · 71 = 7·393
(1 + 7-2 + 7) · 7x = 7·393
(1 + 1/49 + 7) · 7x = 7·393
(393/49) · 7x = 7·393
7x = (7·393)·(49/393)
7x = 7·49 = 73
x = 3
$${{\mathtt{7}}}^{{\mathtt{x}}}{\mathtt{\,\small\textbf+\,}}{{\mathtt{7}}}^{\left({\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{2}}\right)}{\mathtt{\,\small\textbf+\,}}{\mathtt{7}}{\mathtt{\,\times\,}}\left({\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\right) = {\mathtt{7}}{\mathtt{\,\times\,}}{\mathtt{393}} \Rightarrow {\mathtt{x}} = {\mathtt{\,-\,}}{\frac{\left({\mathtt{50}}{\mathtt{\,\times\,}}{{\mathtt{7}}}^{\left({\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{2}}\right)}{\mathtt{\,-\,}}{\mathtt{2\,744}}\right)}{{\mathtt{7}}}}$$
Easy one and difficulty:normal