The first one is one, because 16x and -16x cancel eachother out, the second one on the other hand is not because 2 negatives do not cancel each other, but instead, add together. the third one yes, because when you foil 4x2 times 4x2 = 16x4. the -8 x 4x2 and 8 x 4x2 cancel eachother out, leaving you with -8 x 8, which equals -64, thus 16x4 - 64. the 4th one yes, because 16x2 x x2 = 16x4, and 16 x 2 = 32, x -2 equals -64.the last one, no because while 4 x 4x4 IS 16x4, 4 x -8 is 32
