What two numbers multiply to -81 and add up to 80?

Here we answer the question: "What two numbers multiply to -81 and add up to 80?"

The answer to your question is:

-1 and 81

Below we illustrate and prove that -1 and 81 multiply to -81 and add up to 80:

-1 × 81 = -81
-1 + 81 = 80

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

x² + 80x - 81 = 0

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

(x - 1 ) (x + 81)

To summarize, since -1 and 81 multiply to -81 and add up 80, you know that the following is true:

x² + 80x - 81 = (x - 1 ) (x + 81)

Multiply To One Number and Add Up To Another
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