Math(Quadratic Functions)
posted by Heaven
Determine the quadratic function, f(x), with x intercepts at x=7 and x=2 and y intercept at y=5.
I have been struggling with this question for days. I have phoned my teacher and gotten her help, but I still can't figure it out. If someone could please help me with this, that would be great. Thanks

Reiny
For days ????
since the xintercepts of a function are the same as the roots of the corresponding equation
x=7 > a factor of (x7)
x=2 > a factor of (x+2)
so f(x) = a(x7)(x+2)
we are told that (0,5) lies on it, so
5 = a(7)(2)
a = 5/14
f(x) = (5/14)(x7)(x+2)
or
f(x) = (5/14)x^2  (25/14)x + 5
check:
https://www.wolframalpha.com/input/?i=solve+(5%2F14)x%5E2++(25%2F14)x+%2B+5%3D0
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