Answer:
(x-3) (x-5)
Explanation:
x²−8x+15
note that the constant term is 15 and the x-coefficient is -8
step 1: List factors of 15 : ±1, ±3, ±5, ±15
step 2: observe the factors listed and ask ourselves the following questions:
1) What 2 factors in the list , when multiplied gives the constant 15
2) What same 2 factors when added gives the x-coefficient -8
by deduction or trial and error, we can see that -3 and -5, when multiplied gives 15 and when added gives -8. Hence these become the factors.
Hence the factors are
(x-3) (x-5)