Answer:
hello : here is a general - method
x² + 9x + 8 = x²+(a+b)x+ab
you have the system : a + b = 9 .......(1)
ab = 8 ........(2)
solve this system : by (1) : b = 9 - a
subsct in (2) : a(9 - a ) = 8
9a - a² = 8
a² - 9a +8 = 0
calculate Δ = (-9)² - 4(1)(8) = 81 - 32 = 49 = 7²
a1 = ( 9-7)/2 = 2/2 =1 a2 = (9+7)/2 = 16/2 = 8
if : a = 1 b = 9-1 = 8 if : a = 8 b = 9-8 = 1
factor the polynomial x²+9x+8 = (x+1)(x+8)
