The cost of taking classes at a studio is the same as another studio whose base rate is $35 to join and $4.50 per class. write an equation that may represent the cost of taking classes at this studio?

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.