Question

Factor the given polynomial x^2-17x+72

Answer 1

You need to find 2 numbers whose product is + 72 and when added give - 17.
These 2 numbers are -8 and -9 

so the factors are   ( x - 8)(x - 9)

Answer 2

(x-9)(x-8)   <--- answer

x^2-8x-9x-72

x^2-17x-72