# SOLUTION: How do you get the quadratic equation if you are given a table of values?

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 Question 567835: How do you get the quadratic equation if you are given a table of values?Answer by issacodegard(60)   (Show Source): You can put this solution on YOUR website!You must be given at least 3 points, call them (x1,y1),(x2,y2),(x3,y3). Then we know the equation has the form f(x)=ax^2+bx+c. We get a system of 3 equations in 3 unknowns. Solving for a,b,c in, gives you the equation for f(x). I'll give an example, If we know that three points are (-1,-2),(1,4),(2,13). Then we set up three equations about a,b,c that we know: So we have, We need to solve for a,b,c. So, we subtract eqn1 from eqn2 to get, Divide eqn2 by 2 to get b=3. Then, we have So, Subtract the first eqn from the second to get, Divide the second eqn by 3 to get a=2. Then we have So, Therefore we find that