MATH
posted by Sarah on .
(2,14),(1,1),(3,35)
Find the quadratic function y=ax^2+bx+c
1) 4a+2b+c=14
2) a+b+c=1
3) 9a+3b+c= 35
equation 1&2 = 3a + b = 13
equation 1&3 = 5a +5b = 21

It is easier if you write y as:
y = A (x1)(x3) + B(x2)(x3) +
C(x2)(x1)
y(1) = 1 >
2 B = 1 >
B = 1/2
y(2) = 14 >
A = 14
y(3) = 35 >
C = 35/2
So, we have:
y = 14(x1)(x3) 1/2 (x2)(x3) +
35/2 (x2)(x1) =
3 x^2 + 6 x 10