What two numbers multiply to -399 and add up to -398?

Here we answer the question: "What two numbers multiply to -399 and add up to -398?"

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 -398:

-399 × 1 = -399
-399 + 1 = -398

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

x² - 398x - 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 -398, you know that the following is true:

x² - 398x - 399 = (x - 399 ) (x + 1)

Multiply To One Number and Add Up To Another
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