What two numbers multiply to 639 and add up to -80?

Here we answer the question: "What two numbers multiply to 639 and add up to -80?"

The answer to your question is:

-71 and -9

Below we illustrate and prove that -71 and -9 multiply to 639 and add up to -80:

-71 × -9 = 639
-71 + -9 = -80

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

x² - 80x + 639 = 0

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

(x - 71 ) (x - 9)

To summarize, since -71 and -9 multiply to 639 and add up -80, you know that the following is true:

x² - 80x + 639 = (x - 71 ) (x - 9)

Multiply To One Number and Add Up To Another
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