Which expression is defined for all real numbers?
Please explain why the choice that you chose is correct.
Choice 1)
x+3/x^2
Choice 2)
4/(x-2)^2
Choice 3)
5/(x+2)^2
Choice 4)
7/x^2+3
They are asking which of the choices is not defined for all real numbers. skeeter told you that you can't divide by 0. So in choice 1 can we let x = 0?
Also, please use parenthesis.
Choice 1 reads $\displaystyle x + \frac{3}{x^2}$ and I'm betting it's supposed to be $\displaystyle \frac{x+3}{x^2}$. These are very different expressions. What you need to write in this case is (x + 3)/x^2.
Similarly choice 4 reads $\displaystyle \frac{7}{x^2} + 3$. Again I'm guessing it's supposed to be $\displaystyle \frac{7}{x^2 + 3}$. What you need to write in this case is 7/(x^2 + 3).
-Dan