What two numbers multiply to 81 and add up to 18?

Here we answer the question: "What two numbers multiply to 81 and add up to 18?"

The answer to your question is:

9 and 9

Below we illustrate and prove that 9 and 9 multiply to 81 and add up to 18:

9 × 9 = 81
9 + 9 = 18

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

x² + 18x + 81 = 0

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

(x + 9 ) (x + 9)

To summarize, since 9 and 9 multiply to 81 and add up 18, you know that the following is true:

x² + 18x + 81 = (x + 9 ) (x + 9)

Multiply To One Number and Add Up To Another
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