What two numbers multiply to 108 and add up to 21?

Here we answer the question: "What two numbers multiply to 108 and add up to 21?"

The answer to your question is:

9 and 12

Below we illustrate and prove that 9 and 12 multiply to 108 and add up to 21:

9 × 12 = 108
9 + 12 = 21

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

x² + 21x + 108 = 0

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

(x + 9 ) (x + 12)

To summarize, since 9 and 12 multiply to 108 and add up 21, you know that the following is true:

x² + 21x + 108 = (x + 9 ) (x + 12)

Multiply To One Number and Add Up To Another
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