If a pyramid with a square base is set on top of a cube and exactly covers the top, how many faces will the shape have on the outside

So there are 5 on a pyramid and 6 on a cube, which is 11 - but if you put one on top of the other you take away 2 so the answer is 9

=(5r − 4)(r^2 − 6r + 4)
multiply each term in left parentheses by each term in right parentheses

=(5r*r^2) + (5r*-6r) + (5r*4) + (-4*r^2) +
(-4*-6r) + (-4*4)
multiply

=5r^3 - 30r + 20r - 4r^2 + 24r - 16
combine like terms

=5r^3 - 4r^2 + (-30r + 20r + 24r) - 16

=5r^3 - 4r^2 + 14r - 16

ANSWER: 5r^3 - 4r^2 + 14r - 16 (2nd answer given)

Hope this helps! :)