A system of equations is shown below. (x - 3y = 1
5x + 2y = 4
Which of the following describes two possible first
steps in correctly solving the system using the
elimination method?
A. Multiply the first equation by -5 and then add the
two equations.
B. Multiply the first equation by 4 and then add the
two equations
C. Add 1 to the second equation and then add the
two equations.
D. Add -5 to the first equation and then add the
two equations.

For every corresponding pair of cross sections, the area of the cross section of a sphere with radius r is equal to the area of the cross section of a cylinder with radius and height 2r minus the volume of two cones, each with a radius and height of r. a cross section of the sphere is and a cross section of the cylinder minus the cones, taken parallel to the base of cylinder, is the volume of the cylinder with radius r and height 2r is and the volume of each cone with radius r and height r is 1/3 pie r^3. so the volume of the cylinder minus the two cones is therefore, the volume of the cylinder is 4/3pie r^3 by cavalieri's principle. (fill in options are: r/2- r- 2r- an annulus- a circle -1/3pier^3- 2/3pier^3- 4/3pier^3- 5/3pier^3- 2pier^3- 4pier^3)