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

User Parag Soni
by
7.2k 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
8.3k 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
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories