Let f(x)=2x+3x2+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)
+413 
