2. Simplify: (a)
(b)
3. Find, and simplify, the 23d term in the expansion of
4. The weight of an object varies directly as its distance from the center of the earth when it is below the earth's surface, and inversely as the square of its distance from the center when it is above the surface. If an object weighs 10 pounds at the surface, how far above, and how far below the surface will it weigh 9 pounds? (The radius of the earth may be taken as 4000 miles.)
5. Solve the following pair of equations for x and y:
6. Find the value of