I've got a basic understand of differentiation and working the equation of the tangent on a point of a parabola etc

I don't know how to do this question though:

For the curve $\displaystyle y=ax^2+bx+c $, where a,b and c are constants, it is given that at the points (2,12) and (-1,0) the slope of the tangent is 7 and 1 respectively. Find a, b and c.

How do I go about starting this question??