For each of the following functions, $f:\textbf{R}\longrightarrow\textbf{R}$ state whether they are one-to-one, onto, both or neither. Use the following key:

a	neither 1-1 nor onto
b	1-1 but not onto
c	onto but not 1-1
d	both 1-1 and onto = bijective = invertible

 1. $f(x)=x(x-5)(x+5)$
 2. $f(x)=x + 2\left|x\right|$
 3. $f(x)=\sin(x)$
 4. $f(x)=x^3+5$
 5. $f(x)=\left|x\right|$
 6. $f(x)=x^2+2$
 7. $f(x)=e^x$