Find the break-even point for the firm whose cost function \( C \) and revenue function \( R \) are given. \( C(x)=0.2 x+100 ; R(x)=0.4 x \)

What is \( \left(\frac{f}{g}\right)(x) \) ? \[ \begin{array}{l}f(x)=3 x+4 \\ g(x)=x^{2}-2 x\end{array} \] Write your answer as a polynomial or a rational function in simplest form.

13. Simplify. \( \frac{x^{7} y^{6} z}{x^{9} y^{2}} \)

10. Subtract. \( \left(3 x^{2}-5 x-4\right)-\left(x^{2}-4 x+3\right) \)

\( f(x)=\left\{\begin{array}{lll}-(x+1)^{2}+1 & \text { for } & x<2 \\ x-1 & \text { for } & x \geq 5\end{array}\right. \) Find \( f(-1) \)

21. Solve. \( x^{2}+4 x-45=0 \)