Question

Using interval notation , identify the domain for the function!!! Math 3 - 10 points. Help needed

Answer 1

Answer:

The domain by the interval notation is (-∞ , 3)∪(3 , 4)∪(4 , ∞) ⇒ 3rd answer

Step-by-step explanation:

* Lets revise how to find the domain of the function

- The domain is all values of  x  that make the expression defined

- To find where the expression is undefined put the denominator

  equal 0, to get the values of x which make denominator equal to 0

- The domain will be all the real number except those values

* Now lets solve the problem

∵ f(x) = (x² - 9)/(x² - 7x + 12)

- Let the denominator x² − 7x + 12  equal to  0

∵ x² − 7x + 12 = 0 ⇒ factorize it

- Consider the form  x² + bx + c

- Find a pair of integers whose product is c and whose sum is b

- In this case, whose product is 12 and whose sum is −7

- They are -3 and -4

- Write the factored form using these integers.

∴ (x -3)(x - 4) = 0 ⇒ put each bracket = 0

∴ x - 3 = 0 or x - 4 = 0

∵ x - 3 = 0 ⇒ add 3 to both sides

∴ x = 3

∵ x - 4 = 0 ⇒ add 4 to both sides

∴ x = 4

∴ The domain of f(x) is all real number except 3 and 4

* The domain by the interval notation is

 (-∞ , 3)∪(3 , 4)∪(4 , ∞)