help on a quadratic function

Question

I've been working on this problem for a while now and I just can't figure out where i'm going wrong.

 

Find the quadratic function y+ ax^2p+ bx+ c whose graph passes through the given points.

(1,-6) (2,-7) (3,-4)

 

Thanks!

 

update: sorry i should have elaborated, i've substituted in and solved the three main equations.

 

So I have equations

1) a+b+c = -6

2)  4a+2b+c = -7

3) 9a+3b+c = -4

 

and form ehre i thought you added equations 1 and 2

and did the same with equation 1 and 3. but i'm not sure if this is the correct method.

 

Answer 1

Substitute three times, using each of the three (x,y) ordered pairs, getting 3 equations in the three unknowns a, b, c.

 

Solve that system of three linear equations for a, b, c.