# Domains of functions

F(x)=x2-7x and g(x)=5-x2
Domain of (fg)(x) is. .. . .
Domain of (f/g)(x). ..

Result

a = (Correct answer is: R)
b = (Correct answer is: R - { x1,x2 })

#### Solution:

$a=R$
$\ \\ g(x)<>0 \ \\ \ \\ 5-x^2=0 \ \\ -x^2 +5=0 \ \\ x^2 -5=0 \ \\ \ \\ a=1; b=0; c=-5 \ \\ D=b^2 - 4ac=0^2 - 4\cdot 1 \cdot (-5)=20 \ \\ D>0 \ \\ \ \\ x_{1,2}=\dfrac{ -b \pm \sqrt{ D } }{ 2a }=\dfrac{ \pm \sqrt{ 20 } }{ 2 }=\dfrac{ \pm 2 \sqrt{ 5 } }{ 2 } \ \\ x_{1,2}=\pm \sqrt{ 5}=\pm 2.2360679774998 \ \\ x_{1}=\sqrt{ 5}=2.2360679774998 \ \\ x_{2}=- \sqrt{ 5}=-2.2360679774998 \ \\ \ \\ \text{ Factored form of the equation: } \ \\ (x -2.2360679774998) (x +2.2360679774998)=0 \ \\ b=R - \{ x_{1},x_{2} \}=R - \{ 2.2361,(-2.2361) \}$

Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!

Leave us a comment of this math problem and its solution (i.e. if it is still somewhat unclear...):

Be the first to comment!

Tips to related online calculators

## Next similar math problems:

Which of the points belong function f:y= 2x2- 3x + 1 : A(-2, 15) B (3,10) C (1,4)
Write the equation of the quadratic function which includes points A (-1, 10), B (2, 19), C (1,4)
3. Equation
Eequation f(x) = 0 has roots x1 = 64, x2 = 100, x3 = 25, x4 = 49. How many roots have equation f(x2) = 0 ?
4. Expressions 3
If k(x+6)= 4x2 + 20, what is k(10)=?
5. College 2
College student is moving into a dormitory. The student rent a truck for $19.95 plus$0.99 per mile. Before returning the truck the student fills the tank with gasoline, which cost $65.32. Total cost$144.67. Using a linear equation, explain the process t
Find the roots of the quadratic equation: 3x2-4x + (-4) = 0.
7. Discriminant
Determine the discriminant of the equation: ?
8. Equation
Equation ? has one root x1 = 8. Determine the coefficient b and the second root x2.
9. Roots
Determine the quadratic equation absolute coefficient q, that the equation has a real double root and the root x calculate: ?
Quadratic equation ? has roots x1 = -26 and x2 = -86. Calculate the coefficients b and c.
11. Combinations
From how many elements we can create 990 combinations 2nd class without repeating?
12. Solve 3
Solve quadratic equation: (6n+1) (4n-1) = 3n2
13. Median
The number of missed hours was recorded in 11 pupils: 5,12,6,8,10,7,5,110,2,5,6. Determine the median.
14. Lottery
Fernando has two lottery tickets each from other lottery. In the first is 973 000 lottery tickets from them wins 687 000, the second has 1425 000 lottery tickets from them wins 1425 000 tickets. What is the probability that at least one Fernando's ticket w
15. Class - boys and girls
In the class are 60% boys and 40% girls. Long hair has 10% boys and 80% girls. a) What is the probability that a randomly chosen person has long hair? b) The selected person has long hair. What is the probability that it is a girl?
16. Theorem prove
We want to prove the sentence: If the natural number n is divisible by six, then n is divisible by three. From what assumption we started?
17. Is complex
Are these numbers 2i, 4i, 2i + 1, 8i, 2i + 3, 4 + 7i, 8i, 8i + 4, 5i, 6i, 3i complex?