6) \( \left\{\begin{array}{l}x^{2}-2 y^{2}=1 \\ x^{4}+3 y^{4}=129\end{array}\right. \)

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

Question 3 A store is selling a large selection of men's shirts, and every shirt has the same price. Kiyoshi buys 6 shirts and gets a \( \$ 30 \) discount. His friend Gregory buys 4 shirts and does not receive a discount. Gregory spends \( \$ 20 \) less than Kiyoshi. What is the price of one shirt without any discount? \( \$ 25 \) \$ \( \$ 5 \) \$ \( \$ 100 \) \( \$ 80 \)

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. \( \$ 675 \)

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

e) \( (3 x+2) \cdot\left(x^{3}-2 x^{2}+1\right)= \)