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# find the domain and range of following function?

3x/x^2-81

### 4 Answers

- RayLv 79 years agoFavorite Answer
Domain is all real numbers except x=+-9

Range is all real numbers since 3x/(x^2-81) can be set equal to any real number y and have real solutions for x.

- husseinLv 59 years ago
i think you should better try to understand the concept than having to have to put the question in yahoo every time.

the domain of a function is simply the set of all the x's that u can plug into the equation and get a real answer. in other words we count out the values of x that would lead us to dividing by 0, having the log of 0, or the square root of a negative number. since the equation above doesnt have square roots or logs, we should only concentrate on avoiding division by zero.

this means that all the values that satisfy the equation x^2-81 = 0 are excluded from the domain.

x^2-81 can only be 0 if x is 9 or -9, therefore the domain of the equation is all the real numbers except 9 and -9

the range of a function is the set of all the values that the function can output. in other words, all the answers we can get by plugging in different values of x

in the above function there are no values that cant be achieved , in other words, if we set the above function equal to any number, we can still find real values of x.

so the domain is all real numbers except +-9

the range is all real numbers

good luck.

- 9 years ago
Based off the denominator:

x^2-81

(x+9)(x-9)

Domain: All real numbers except xâ -9, 9

- Man of SteelLv 69 years ago
function is undefined where the denominator is equal to zero.

x^2-81=0

x^2=81

x=9 or x=-9.

domain: all real numbers except for x=9 and x=-9

range: all real numbers.