(s+1)2= b2-100= 36+12c+c2= (8c-5k)(5k+8c)= (4p+3t)2= 9b2-400d2= .!

(s + 1)^2 = s^2 + 2s + 1 
b^2 - 100 = (b - 10) (b + 10)
36 + 12c + c^2 = (c + 6)^2
(8c - 5k) (8c + 5k) = (8c)^2 - (5k)^2 = 16c^2 - 25k^2
(4p + 3t)^2 =  16p^2 + 24pt + 9t^2
9b^2 - 400d^2 = (3b - 20d) (3b + 20d)