1. Duas pessoas farão conjuntamente a pintura de um muro, cada uma trabalhando a partir de uma das ex- tremidades. Se uma delas pintar \( \frac{2}{5} \) do muro e a outra os 15 m restantes, a extensão desse muro é de: \( \begin{array}{lll}\text { a) } 25 \mathrm{~m} & \text { b) } 35 \mathrm{~m} & \text { c) } 42 \mathrm{~m} \\ \text { d) } 45 \mathrm{~m} & \text { e) } 20 \mathrm{~m} & \end{array} \)

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

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

5) \( 4(2-x)=x+3 \)

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

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