(x - 8)(x - 5)
Any product of any list of factors is zero, if one of the factors is zero.
Well, honey, in the equation 8x5=40, the two factors are 8 and 5. 8 times 5 equals 40. It's as simple as that, darling.
8, 40 and 200
74 and 40
You didn't bother to list the binomials to choose from, but the two binomial factors of x2 + 6x - 40 are (x + 10) and (x - 4)
16/40 + 15/40 = 31/40
this equals 818
40
40 and 21 have no common prime factors
7 40 plus 2 as the sum of two products can be expressed as 1.47 x 1.47.
25/40 + 16/40 = 41/40 = 1 and 1/40
45 and 40