If x = 5, what is ((x+3)/4)*234

What is the domain of the step function f(x)=[2x]-1?

Can someone tell me if these are correct?

In 2014, the three largest economies in the world were (listed in order, from largest): a) the u.s., china, germany. b) the u.s., china, japan. c) china, the u.s., japan. d) china, the u.s., germany.