Find the set \( A \cap B \). \( \begin{array}{l}U=\{1,2,3,4,5,6,7,8,9\} \\ A=\{1,2,3,7\} \\ B=\{1,2,6\}\end{array} \) Select the correct choice below and, if necessary, fill in the answer box to complete your choice. A. \( A \cap B=\{\square\} \) (Use a comma to separate answers as needed.) B. \( \mathrm{A} \cap \mathrm{B} \) is the empty set.

lake (c) the subject o che formula \( E=m e^{2} \)

\( \begin{array}{lllll}\text { (f) } 4 \frac{1}{2}+3 \frac{4}{5} & \text { (g) } 6 \frac{2}{3}+4 \frac{8}{9} & \text { (h) } 4 \frac{5}{6}+3 \frac{1}{3} & \text { (i) } 4 \frac{3}{8}+6 \frac{3}{4} & \text { (j) } 6 \frac{1}{2}+4 \frac{3}{10} \\ \text { (k) } 2 \frac{5}{9}+3 \frac{2}{3} & \text { (l) } 6 \frac{7}{10}+4 \frac{3}{5} & \text { (m) } 4 \frac{11}{12}+2 \frac{2}{3} & \text { (n) } 5 \frac{7}{9}+2 \frac{2}{3} & \text { (o) } 2 \frac{4}{5}+4 \frac{7}{10} \\ \text { (p) } 2 \frac{1}{4}+2 \frac{1}{5} & \text { (q) } 5 \frac{1}{2}+3 \frac{4}{7} & \text { (r) } 6 \frac{2}{3}+4 \frac{3}{5} & \text { (s) } 3 \frac{3}{4}+4 \frac{4}{5} & \text { (t) } 7 \frac{3}{8}+4 \frac{1}{3}\end{array} \)

The cost, in thousands of dollars, of airing \( x \) television commercials during a sports event is given by \[ C(x)=150+2,400 x-0.08 x^{2} \] (a) Find the marginal cost function \( C^{\prime}(x) \). \( C^{\prime}(x)=2400-0.16 x \) (b) Use the marginal cost to approximate the cost to air the 5 th commercial. Convert your answer to dollars. The cost to air the 5 th commercial is approximately 2399360 (c) What is the exact cost to air the 5 th commercial? Convert your answer to dollars. The exact cost to air the 5 th commercial is

Simplify \( \left(\frac{4 a^{3} b}{\sqrt{c}}\right)^{2} \)

Find the first and second derivatives. \( s=\frac{t^{5}+3 t^{4}-4}{t^{5}} \)