To evaluate (4^3)^4, do i need to subtract multiply or add

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10

Carmen ayer en el mercado compro 3/4 kg de guayabas, 6/8 kg de peras, 1/2 kg de naranjas ¿cuantos kilogramos de fruta compro?

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )