128k views
5 votes
Find the zeros of the function. f(x)=9x^2-12x-5

User Parag Soni
by
6.3k points

2 Answers

3 votes
x=5/3, -1/3

You can use the quadratic formula or you can do any method that your teacher teaches you (box, etc.)
User Mhkeller
by
6.8k points
6 votes
Answer: 5/3 and - 1/3

Step-by-step explanation:

1) Set the given function equal to 0: 9x^2 - 12x - 5 = 0

2) make 9x^2 = (3x)^2 and 12x = 4(3x)

=> (3x)^2 - 4(3x) - 5 = 0

3) Factor the polynomial:

(3x - )(3x + ) first stept of factoring.

Now find two numbers that sum - 4 and their product of - 5, those are -5 and + 1: =>

(3x - 5) (3x + 1) = 0

4) Set the two factors equal to 0:

3x - 5 = 0 => 3x = 5 => x = 5/3 ↔ one root

3x + 1 = 0 => 3x = - 1 => x = - 1/3 ↔ the other root.
User SCdF
by
7.0k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.