Question

Which function has x-intercepts of 3 and 8 and contains the point (-1, -2)?

Answer 1

what would be the "roots" of that function you'd think?

Answer 2

Are there choices?

Answer 3

hmm so... got roots? =)

Answer 4

y=-1/36(x-3)(x-8)
y=-1/14(x-3)(x-8)
y=-1/18(x-3)(x-8)
y=-1/7(x-3)(x-8)

Answer 5

I don't get what your asking

Answer 6

have you done quadratic equations yet?

Answer 7

A function that has x-intercepts a, b, c, ... has factors of (x - a), (x - b), (x - c), etc.

For example, if a function has roots of 2 and -5, then the function is made up of the factors (x - 2) and (x - (-5)), or (x + 5). The function is y = (x - 2)(x + 5).

In your case, you have roots 3 and 8. From this you know the function must include these factors: (x - 3) and (x - 8).
That means you have to have y = k(x - 3)(x - 8)
Now take y = k(x - 3)(x - 8), plug in (-1, -2) and figure out what k is equal to.

Answer 8

thanks everyone

Answer 9

You're welcome.