find all# for the rational expression 8/x^2+4?

Answer 1

by finding all the rational expression, you are getting the range. usually, the range is all real numbers, unless there is a variable in a denominator, or a root.
the term has the denominator x^2 + 4. if the denominator is equal to zero, the whole equation will become undefined. so, x^2 + 4 must not be equal to zero. since there are no values which can make it zero, the range of the expression is the set of all real numbers.