x² - 13x - 40 = 0
To solve this polynomial equation, we will first factor the left side.
On the left, we have a special type of trinomial
that can be factored as the product of two binomials.
X² breaks down as x · x and we are looking for
the factors of 40 that add to the middle term, -13.
Since the middle term is negative, we use negative factors of 40.
The factors that work are -8 and -5.
So we have (x - 8)(x - 5) = 0.
If (x - 8)(x - 5) = 0, that means that either x - 8 = 0 or x - 5 = 0.
Solving for x in each equation, we have x = 8 or x = 5.
We can write this as the set of numbers {8, 5}.
