Find y. Round to the nearest tenth? Please help me!

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?

The graph of f(x) is obtained by reflecting the graph of f(x)=-3|x| over the x-axis. which equation describes f(x)? a) f(x)=3|x| b) f(x)=|x+3| c) f(x)=-3|x| d) f(x) = - |x+3|

If log_3(x)=4.5 and log_3(y)=3, what is log_3(x^2/y)? a. 3b. 6.75c. 6d. 1.5