What two numbers multiply to 648 and add up to -81?

Here we answer the question: "What two numbers multiply to 648 and add up to -81?"

The answer to your question is:

-72 and -9

Below we illustrate and prove that -72 and -9 multiply to 648 and add up to -81:

-72 × -9 = 648
-72 + -9 = -81

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

x² - 81x + 648 = 0

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

(x - 72 ) (x - 9)

To summarize, since -72 and -9 multiply to 648 and add up -81, you know that the following is true:

x² - 81x + 648 = (x - 72 ) (x - 9)

Multiply To One Number and Add Up To Another
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