Is the solution strategy used in solving the linear equation correct? If it is correct, show the final step (check the solution). If it is not correct, explain why.

\[ \begin{aligned} 7+4(2+5 x) & =3(6 x+7)-(13 x+36) \\ 7+8+20 x & =18 x+21-13 x-36 \\ 15+20 x & =5 x-15 \\ 15+20 x-\mathbf{5 x} & =5 x-15-\mathbf{5} x \\ 15+15 x-\mathbf{1 5} & =-15-\mathbf{1 5} \\ 15 x & =-30 \\ x & =-2 \end{aligned} \]