Question

find the domain of the function f(x)= 3x-8/x^2-9x+20

Answer 1

Answer:

Step-by-step explanation:

factorise the denominator

x^2 - 9x +20

x^2 -5x - 4x +20

x(x-5)-4(x-5)

(x-5)(x-4)

the domain is all real numbers except 4 & 5

the answer for ur question is given

hope it helps u

plssss mark me brainliest

plllllssssss follow me

Answer 2

Answer:

$\Large\boxed{X=5, X=4}$

Step-by-step explanation:

Given:

$\Large\boxed{\textnormal{LESSON: DOMAIN OF THE FUNCTION}}$

To find the domain, first you have to use the function notation of f(x).

Solutions:

First, thing you do is take out the denominator from left to right numbers.

$\displaystyle \frac{3x-8}{x^2-9x+20}$

Solve.

$\displaystyle x^2-9x+20=0$

Try to used quadratic equation formula.

$\Large\boxed{\textnormal{QUADRATIC EQUATIONS FORMULA}}$

$\displaystyle AX^2+BX+C=0$

$\displaystyle X_1, _2=\frac{-B\pm\sqrt{B^2-4AC} }{2A}$

A=1

B=(-9)

C=20

$\displaystyle \frac{-(-9)\pm \sqrt{(-9)^2-4*1*20}}{2*1}$

Solve.

$\displaystyle 9+\sqrt{(-9)^2-4*1*20}=10$

$\displaystyle (-9)^2=81$

$\displaystyle 4*1*20=80$

Subtract the numbers from left to right.

$\displaystyle \sqrt{81-80}$

$\displaystyle 81-80=1$

$\displaystyle \sqrt{1}=1$

Add the numbers from left to right.

$\displaystyle 9+1=10$

$\displaystyle \frac{10}{2*1}$

Multiply.

$\displaystyle 1*2=2$

$\displaystyle \frac{10}{2}$

Then, divide the numbers from left to right.

$\displaystyle 10\div2=\boxed{5}$

$\displaystyle \frac{-(-9)-\sqrt{(-9)^2-4*1*20}}{2*1}=\boxed{4}$

$\Large\boxed{X=5, X=4}$

Therefore, the correct answer is x=5 and x=4.