Math Problem

[JSchnett]

This problem is extra credit and I can't figure it out

Find g(x), if g is a quadratic,
g(-1)=-2
g(1)=4
g(2)=13

show some kind of work if possible
thanks

[evank15]

Function of the form ax^2 + bx + c. Using the initial conditions, we can find three equations.

a-b+c=-2

a+b+c=4

4a+2b+c=13

3 equations, three unknowns, solve the system. Might want to check my work, though. I'm 4 tabling right now and I might have f'd up.

[evank15]

I think you will find that it follows that a=2, b=3, c=1.

[Jasper109]

Everything is correct, except c=-1.

Once you have the 3 equations with 3 unknowns, you can do a systems of equations method or set it up as a matrix.

Most graphing calculators will also be able to solve it once you have the 3 equations.

[evank15]

Ya whoops I had that, just didn't type it out properly!
Very sorry if I caused any confusion.

[JSchnett]

thank you very much

[CityFan]

erm,

g(x) = a x^2 + b x + c

a - b + c = -2
a + b + c = 4
4a + 2b + c = 13

Solve for a, b and c.

If that's extra credit, what do you do for normal credit?

[CityFan]

[ QUOTE ]
Everything is correct, except c=-1.

Once you have the 3 equations with 3 unknowns, you can do a systems of equations method or set it up as a matrix.

Most graphing calculators will also be able to solve it once you have the 3 equations.

[/ QUOTE ]

If you need a "matrix method", or a calculator, or any "method" other than elementary algebra, you would get no credit on my course. (Fortunately I don't have a course).