I have the slope of a tangent line and the curve but I have to find the point(s)

Question

Find the point(s) where the slope of a tangent line to the given curve has the value of $y=2x^2$, $mtan= -4$

I know how to solve for mtan with the points but I don't know to find the points.

Answer 1

$y = 2x^2$

$\frac{dy}{dx} = 4x$

$\frac{dy}{dx}$ is slope of a tangent line. Also $m\tan$ is slope of a tangent. On comparing,

$4x = -4$

$x = -1$

Put value of $x$ in equation $y = 2x^2$.

$y = 2$