Answer :
s² - 16s - 57 = s² - 16s + 64 - 121 = s² - 2*1*8 + 8² - (11)² =
we use the formula a² - 2ab + b² = (a-b)²
(s - 8)² - (11)²
we use the formula a² - b² = (a+b)*(a-b)
(s - 8 )² - (11)²
a² - b²
[ (S - 8) - 11] * [ (S-8) + 11] = [S-19] * [S+3]
we use the formula a² - 2ab + b² = (a-b)²
(s - 8)² - (11)²
we use the formula a² - b² = (a+b)*(a-b)
(s - 8 )² - (11)²
a² - b²
[ (S - 8) - 11] * [ (S-8) + 11] = [S-19] * [S+3]