-7(2x + 1) + 3(5x – 4) = 0

$${\mathtt{\,-\,}}{\mathtt{7}}{\mathtt{\,\times\,}}\left({\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,\small\textbf+\,}}{\mathtt{1}}\right){\mathtt{\,\small\textbf+\,}}{\mathtt{3}}{\mathtt{\,\times\,}}\left({\mathtt{5}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{4}}\right) = {\mathtt{0}}$$

$${\mathtt{\,-\,}}{\mathtt{14}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{7}}{\mathtt{\,\small\textbf+\,}}{\mathtt{15}}{\mathtt{\,\times\,}}{\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{12}} = {\mathtt{0}}$$

$${\mathtt{x}}{\mathtt{\,-\,}}{\mathtt{19}} = {\mathtt{0}}$$

$${\mathtt{x}} = {\mathtt{19}}$$

.

-7(2x + 1) + 3(5x - 4)  =  0

Use the Distributive Property:  -7(2x) + (-7)(1) + 3(5x) + 3(-4)  =  0

Multiply:                                                  -14x - 7 + 15x - 12  =  0

Simplify:                                                                     x - 19  =  0

Add 21 to both sides:                                                          x  =  19