Which of the following is equivalent to ln 4x + 5 lnx - ln 2xy?
ln (8x7y)
In (4x6 - 2xy)
5 In 4x / In 2y
In (2x^5 / y)

Use stokes' theorem to evaluate c f · dr where c is oriented counterclockwise as viewed from above. f(x, y, z) = xyi + 5zj + 7yk, c is the curve of intersection of the plane x + z = 8 and the cylinder x2 + y2 = 81.