4)) Solve using substitution. \( \begin{array}{l}x=-1 \\ -2 x-9 y=-16\end{array} \) Submit

To solve the system using substitution, we first take the equation \( x = -1 \) and substitute it into the second equation. So, we replace \( x \) in the second equation with \(-1\): \[ -2(-1) - 9y = -16 \] This simplifies to: \[ 2 - 9y = -16 \] Now, isolate \( y \) by subtracting 2 from both sides: \[ -9y = -16 - 2 \] \[ -9y = -18 \] Finally, divide both sides by -9 to solve for \( y \): \[ y = 2 \] Thus, the solution to the system of equations is \( x = -1 \) and \( y = 2 \).