\( \sqrt{5} \cdot \sqrt{18}=\quad \) c) \( \left(2^{3} \cdot 2^{3}\right)^{9}:\left(2^{2} \cdot 2^{5}\right)^{7}= \)

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? \( \$ 25 \) \$ \( \$ 5 \) \$ \( \$ 100 \) \( \$ 80 \)

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

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

Which of the following equations has no solution \( \begin{array}{l}x+20-5 x=7(3+x)-3 x \\ \begin{array}{l}5 x+20-7 x=7(3+x)-3 x \\ 5 x+21-x=7(3+x)-3 x \\ 5 x+20-x=7(3+x)-3 x\end{array} \\ \begin{array}{l}5\end{array}\end{array} \$ \begin{array}{l}\text { - }\end{array} \)