What two numbers multiply to 399 and add up to -40?

Here we answer the question: "What two numbers multiply to 399 and add up to -40?"

The answer to your question is:

-21 and -19

Below we illustrate and prove that -21 and -19 multiply to 399 and add up to -40:

-21 × -19 = 399
-21 + -19 = -40

Are you asking because you are trying to figure out how to factor the following quadratic equation?

x² - 40x + 399 = 0

If so, the solution to factor the quadratic equation above is:

(x - 21 ) (x - 19)

To summarize, since -21 and -19 multiply to 399 and add up -40, you know that the following is true:

x² - 40x + 399 = (x - 21 ) (x - 19)

Multiply To One Number and Add Up To Another
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