What two numbers multiply to 399 and add up to -400?

Here we answer the question: "What two numbers multiply to 399 and add up to -400?"

The answer to your question is:

-399 and -1

Below we illustrate and prove that -399 and -1 multiply to 399 and add up to -400:

-399 × -1 = 399
-399 + -1 = -400

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

x² - 400x + 399 = 0

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

(x - 399 ) (x - 1)

To summarize, since -399 and -1 multiply to 399 and add up -400, you know that the following is true:

x² - 400x + 399 = (x - 399 ) (x - 1)

Multiply To One Number and Add Up To Another
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