Find the zeros of the polynomial function.

f(x) = x^2 – 9x – 70

Question

Find the zeros of the polynomial function.

f(x) = x^2 – 9x – 70

jjuden · Answer

a –10, 3
      b –14, 5
      c –3, 10
      d –5, 14

tkhunny · Answer

Have you considered Factoring?
Have you considered Completing the Square?
Have you considered The Quadratic Formula?

tkhunny · Answer

The product must be -70.  Do you know why?

a –10, 3 Product -30 -- Nope
b –14, 5 Product -70 -- Yup
c –3, 10 Product -30 -- Nope
d –5, 14 Product -70 -- Yup

Okay, that narrowed it down to b and d.  Now what?

jjuden · Answer

no

jjuden · Answer

add them

tkhunny · Answer

The sum must be -9.  Do you know why?

b –14, 5 Sum -9 -- Yup
d –5, 14 Sum 9 -- Nope

We have solve the problem, but your "no" on my first questions, and I'm guessing "no" on my second do not fill me with confidence that you understand what just happened.

Submit another problem and this time, you solve it.