What two numbers multiply to -810 and add up to 81?

Here we answer the question: "What two numbers multiply to -810 and add up to 81?"

The answer to your question is:

-9 and 90

Below we illustrate and prove that -9 and 90 multiply to -810 and add up to 81:

-9 × 90 = -810
-9 + 90 = 81

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

x² + 81x - 810 = 0

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

(x - 9 ) (x + 90)

To summarize, since -9 and 90 multiply to -810 and add up 81, you know that the following is true:

x² + 81x - 810 = (x - 9 ) (x + 90)

Multiply To One Number and Add Up To Another
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