What's the value of a+b+c?

Question

If y=ax²+bx+c passes through points (-3,10), (0,1), and (2,15), what's the value of a+b+c?

Answer 1

Start by substituting (0,1) into the formula; this gives c = 1.

next, substitute (-3,10) and (2,15); this gives you two equations with two unknowns, a and b.  Solve that system.

Then you have a, b and c; add them up.