8. A company has a fixed cost of \( \$ 2,000 \) and a variable cost of \( \$ 10 \) per unit for producing a product. Which of the following is the correct cost function \( C(x) \), where \( x \) represents the number of units produced? \( \begin{array}{ll}\text { a. } C(x)=2000 x+10 & \text { c. } C(x)=10 x-2000 \\ \text { b. } C(x)=2000+10 x & \text { d. } C(x)=2000-10 x\end{array} \)

Q47. Divide 24 in three parts such that they are in AP and their product is 440 .

\( \leftarrow \begin{array}{l}\text { Multiply. } \\ \left(6 x^{2}+7\right)^{2} \\ \left(6 x^{2}+7\right)^{2}=\square \text { (Do not factor.) }\end{array} \)

Multiply. \[ (x+5)(x+6) \] \( (x+5)(x+6)=\square \) (Simplify your answer.)

Multiply. \( \left(7 x^{2}+2\right)\left(6 x^{2}+5\right) \) \( \left(7 x^{2}+2\right)\left(6 x^{2}+5\right)=\square \)

Multiply. \[ \left(x+\frac{2}{7}\right)\left(x-\frac{1}{7}\right) \] \( \left(x+\frac{2}{7}\right)\left(x-\frac{1}{7}\right)=\square \) (Use integers or fractions for any numbers in the expression.)