What two numbers multiply to 80 and add up to -21?

Here we answer the question: "What two numbers multiply to 80 and add up to -21?"

The answer to your question is:

-16 and -5

Below we illustrate and prove that -16 and -5 multiply to 80 and add up to -21:

-16 × -5 = 80
-16 + -5 = -21

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

x² - 21x + 80 = 0

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

(x - 16 ) (x - 5)

To summarize, since -16 and -5 multiply to 80 and add up -21, you know that the following is true:

x² - 21x + 80 = (x - 16 ) (x - 5)

Multiply To One Number and Add Up To Another
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