Chapter 9 - Solving Quadratic Equations - 9.2 - Solving Quadratic Equations by Graphing - Exercises - Page 494: 26

See the explanation

Here, the solution is considered the intersection of the parabola and the $y$-axis (the $y$-intercept), that is not correct. The solution is the $x$-intercept which is the $x$-coordinate of the intersection (or touch) of the parabola and the $x$-axis, that is $x=-3$.