What is 10t =90 and how do i solve this?

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)

Lines b and c are parallel. what is the measure of 2? m2 = 31° m2 = 50° m2 = 120° m2 = 130°

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?