Solve the system by substitution.
\[
\begin{array}{l}
7 x+2 y=-49 \\
-x+y=16
\end{array}
\]

Step 1 ：Given the system of equations: \[\begin{array}{l} 7x + 2y = -49 \ -x + y = 16 \end{array}\]

Step 2 ：We can express one variable in terms of the other from one equation and substitute this expression into the other equation. From the second equation, we can express y in terms of x: \(y = x + 16\)

Step 3 ：Substitute \(y = x + 16\) into the first equation, we get: \(7x + 2(x + 16) = -49\)

Step 4 ：Solving this equation, we find that \(x = -9\)

Step 5 ：Substitute \(x = -9\) back into the equation \(y = x + 16\), we find that \(y = 7\)

Step 6 ：\(\boxed{x = -9}\) and \(\boxed{y = 7}\) are the solutions to the system of equations