(y-s) (y+s) = y²-s²
(5-z) (5+z) = 5²-z² = 25-z²
(t+7) (7-t) = (7+t) (7-t) = 7²-t² = 49-t²
7(a+4) (a-4) = 7 (a²-4²) = 7 (a²-16) = 7a² - 112
x (x-7) (x+7) = x(x²-7²) = x(x²-49) = x³-49x
4b(b+3) (3-b) = 4b (3²-b²) = 4b (9-b²) = 36b - 4b³
3y²(-y-2) (2-y) = -3y² (2+y) (2-y) = -3y² (2²-y²) =-3y² (4-y²) = -12y²+y⁴