What two numbers multiply to -646 and add up to 21?

Here we answer the question: "What two numbers multiply to -646 and add up to 21?"

The answer to your question is:

-17 and 38

Below we illustrate and prove that -17 and 38 multiply to -646 and add up to 21:

-17 × 38 = -646
-17 + 38 = 21

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

x² + 21x - 646 = 0

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

(x - 17 ) (x + 38)

To summarize, since -17 and 38 multiply to -646 and add up 21, you know that the following is true:

x² + 21x - 646 = (x - 17 ) (x + 38)

Multiply To One Number and Add Up To Another
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