Math
posted by Sandy .
What is the domain of
f(x) = √(x^22x8)
Thanks!

When the leading coefficient a is positive, the parabola opens up ( concave up )
For function:
x ^ 2  2 x  8
the leading coefficient is a = 1
function is concave up
When the parabola ia concawe up all walues between roots are negative.
No negative number can have a real square root.
Funtions zerro points are :
 2 and 4
So domain of your fuction:
(  infinity , 2 ] U [ 4 ,infinity )
OR
x <= 2 and x >= 4
If you don't knowe how to solve equation:
x ^ 2  2 x  8 = 0
In google type:
quadratic equation online
When you see list of results click on:
Free Online Quadratic Equation Solver:Solve by Quadratic Formula
When page be open in rectangle type:
x ^ 2  2 x  8 = 0
and click option: solve it!
You wil see solution stepbystep
If you want graph of functions:
Go on :
wolframalpha dot com
When page be open in rectangle type :
x ^ 2  2 x  8
and click option =
after few seconds yo will everythig about function
Then type :
sqrt ( x ^ 2  2 x  8 )
and click option =
P.S.
Sorry for My bad English
Respond to this Question
Similar Questions

Algebra
How would i complete these problems? 1. (√6mn)^5 2. ^3√16x  ^3√2x^4 3.^4√x • ^3√2x 4. ^3√72x^8 5. √63a^5b • √27a^6b^4 and are these problems correct? 
Math
Find an equation of the line that bisects the obtuse angles formed by the lines with equations 3xy=1 and x+y=2. a. (3√2 +√10)x(√10 + √2)y2√10+√2=0 b. (3√2  √10)x+(√10  √2)y+2√10+√2=0 … 
maths
I will be thankfull to you if you help me to solve the below problem: 6√x11/3√x=2√x+1/√x+6 I tried to solve the above problem like this: (6√x11)(√x+6)=(3√x)(2√x+1) 6√x(√x+6)11(√x+6)=(3√x)(2√x)+(3√x)(1) … 
Algebra Work Check
1. 5√6 * 1/6√216 5/6 * √1296 5/6 * √144 * √9 = 30 2. 9√28a^2 * 1/3√63a 3√1764a^3 3√49a^2 * √36a 3*7a*6√a = 126a√a 
8th grade algebra
Can you check my answers? 1. 3√20/√4 = 3√(5)(4)/2 = 3(2)√5/2 = 3√5 2. 4√15/√9 = 4√15/3 3. √12/√16 = √4(3)/4 = 2√3/4 = √3/2 4. √10/√5 = √2 
Algebra
1. Simplify the expression: 4√18+5√32 A.45√2 B.32√2 C.116√2 D.9√50 2. Simplify the expression: 7√53√80 A.5√5 B.4√75 C.5 D.4√75 3. Simplify the expression: √21(√3+√14) … 
Algebra
1.Simplify the radical expression. √5+6√√5 A.5√5 B.7√10 C.7√5 D.5√10 2.Simplify the radical expression. 2√6+3√96 A.14√6 B.14√96 C.5√96 D.50√6 3.Simplify … 
Algebra  Check My Work
For Question 18 Simplify the Radical Expression ***  My Answer 1.√45 3√5*** 2.√180x^2 6x√5*** 3.√150x^3 k^4 5xk^2√6x*** 4.√21y * 5√49y 35y√21*** 5.(The square root sign applies … 
Algebra 1B Radical expressions & data analysis
1. Simplify 2/√5 A. 2/√5 B. √10 C. √10/5 D. 2√10/5 *** My answer 2. Simplify 11√112 A. 44√7 B. 176 √7 C. 27 √7 D. 4√7 *** My answer 3. Simplify 17√17 9 √17 … 
Math
find the value of k in simplest form for which the larger root of x^25x+k=0 is √6+√11 * √3+√3+√11 * √3+√6+√3+√11 * √3√6+√3+√11.