Question

The zero of the function in 9x^2-25/3x+5 is

a. -5/3
b. 5/3
c. 5

**My Answer was "a" please explain how you got your answer.

Answer 1

Is the problem (9x^2-25)/(3x+5)?

Answer 2

Yes.

Answer 3

Please do explain how you got that, so we can fix your thinking about this problem.

Answer 4

were you trying to make the denominator be 0?

Answer 5

There is no= in this problem, so I don't see how you can find a zero.

Answer 6

that's called a pole, not a zero. a zero will have the numerator be equal to 0.

Answer 7

by factoring 9 and 25

Answer 8

but at x = -5/3, the function is undefined due to division by 0. that cant be your zero, you'll have to find another. how many solutions are there to 9x^2-25 = 0?

Answer 9

Here ill show you how it looks on paper.

Answer 10

Ah, so you are trying to find when the numerator is zero. After the factors of (3x+5) cancel, you are left with (3x-5) and 3x-5=0 when x=5/3

Answer 11

Why are they positive numbers if I may ask.

Answer 12

You see that the 3x+5's from the numerator and denominator will cancel, right? And this will leave us with 3x-5. Now just set 3x-5=0. Move the 5 to the other side, making it positive 5, and then divide by 3, making x=5/3.

Answer 13

Thank you.

Answer 14

You are welcome!

Answer 15

Would I graph that answer?

Answer 16

You can. If you have access to a graphing calculator, it will show you where you have a 'pole' as whalmer pointed out earlier at x=-5/3.

Answer 17

alright.