9x = y-3z-21 \( 4 y-6 z=8 x+10 \) \( 56 x-28 y=2-42 z \) a. Write the equations in standard form. b. Predict the number of solutions. Explain your answer. c. Solve the system of equations to verify your prediction.

a) \( \log _{2} x=1-x \);

Suppose the linear regression line \( y=3.009 x \) - 77.131 predicts a pizza parlor's profits based on the number of pizzas sold. If \( x \) represents the number of pizzas sold, and \( y \) represents the pizza partor's profits in dollars, about how much can the plizza parlor expect in profits if it sells 275 pizzas? A. \( \$ 750 \) B. \( \$ 900 \) C. \( \$ 825 \) D. \( \$ 675 \)

3) \( Y+\left[\begin{array}{l}-1 \\ -6\end{array}\right]=\left[\begin{array}{c}10 \\ -14\end{array}\right] \)

a) \( \log _{2} x=1-x \);

6) \( \frac{1}{x-2}=2 \)