Let \[f(x) = \frac{2x + 3}{x^2 + 7}.\] Find the domain of $f$. Give your answer using interval notation.
The only restriction to the domain is an x value that makes the denominator = 0
But notice that
x^2 + 7 = 0
x^2 = -7
And no (real) x makes this true....so....the domain is all real numbers → (-inf, inf)
+306 
