If the points (-1,4) and (2,13) are on the graph of the quadratic function f(x) = 7x^2 + bx + c , what are the values of b and c ?

1 Answer
Mar 1, 2018

we can just put the values of the given points,in the equation f(x) = 7x^2 +bx +c

So,for x=-1,f(x) =4

So, 4 =7-b+c

or, b-c=3...1

And, for x=2,f(x)=13

so, 13=28 +2b+c

or, 2b+c = -15....2

Solving 1 and 2 we get,

b=-4 and, c=-7