One way to solve this system of equations is to use the elimination method. You can solve for one variable in terms of the other using one equation and then substitute that expression into the other equation. For example, you can solve for x in terms of y using the second equation: x = -11 - y. Then substitute this expression for x into the first equation: (-11 - y) * y = -80. Solving this quadratic equation will give you the values of y, and then you can find the corresponding values of x.