For the curve given by

$x=3-t$ and $y=7t^2$

find all the points $($if any$)$ of horizontal and vertical tangency to the curve.

Enter DNE if answer doesn't exist.

Hoizontal tangents: $\frac{dy}{dt}=14t=0$ when $t=0.$Point: $$

Vertical tangents: $\frac{dx}{dt}=-1=0$ when $t=0$ Point: DNE