Enter T or F depending on whether the function is one-to-one or not. (You must enter T or F -- True and False will not work.)

 1. $e(x) = 2 \sqrt{x + 6}$
 2. $b(x) = 2 x^3 - 8 x$
 3. $\displaystyle c(x) = \frac{x - 2}{6 +x}$
 4. $d(x) = (3 x - 2)^2 + 8$
 5. $a(x) = 2 x^4 - 6 x$