Answer:
[tex](0,\, -6)[/tex].
Step-by-step explanation:
On a cartesian plane, the [tex]y[/tex]-intercept of a function is the point where the graph of that function intersects with the [tex]y\![/tex]-axis.
The [tex]y[/tex]-axis of a cartesian plane is the same as the equation [tex]x = 0[/tex] (that is, the collection of all points with an [tex]x[/tex]-coordinate of [tex]0[/tex].)
Construct a system of two equations, with one equation representing [tex]y[/tex]-axis and [tex]y = f(x)[/tex] to represent the graph of this function:
[tex]\begin{aligned}\begin{cases} y = x^{2} + x - 6 & \text{for the quadratic function} \\ x = 0 & \text{for the $y$-axis}\end{cases}\end{aligned}[/tex].
Solve this system for [tex]x[/tex] and for [tex]y[/tex]. If a solution exists, then the [tex]y\![/tex]-axis and the graph of [tex]y = f(x)[/tex] would indeed intersect. The point [tex](x,\, y)[/tex] would be the intersection of the [tex]y\!\![/tex]-axis and the graph of [tex]y = f(x)\![/tex].
Substitute the second equation of the system into the first.
[tex]\begin{aligned}\begin{cases} x = 0 \\ y = -6\end{cases}\end{aligned}[/tex].
Hence, the intersection of the [tex]y[/tex]-axis and the graph of [tex]y = f(x)[/tex] would be [tex](0,\, -6)[/tex]. By definition, this point would be the [tex]y\![/tex]-intercept of [tex]y = f(x)\![/tex].
