Let E be the solid region in the first octant bounded by the planes z =1-x and the plane y =1. Suppose that x, y, and z are measured in centimeters and that the density of E is given by p(x,y,z)=2x grams per cm^(3). Find the mass of the solid region E using three different triple integrals in the orders dx dy dz,dy dx dz, and dz dx dy.