What two numbers multiply to 15 and add up to 8?

Here we answer the question: "What two numbers multiply to 15 and add up to 8?"

The answer to your question is:

3 and 5

Below we illustrate and prove that 3 and 5 multiply to 15 and add up to 8:

3 × 5 = 15
3 + 5 = 8

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

x² + 8x + 15 = 0

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

(x + 3 ) (x + 5)

To summarize, since 3 and 5 multiply to 15 and add up 8, you know that the following is true:

x² + 8x + 15 = (x + 3 ) (x + 5)

Multiply To One Number and Add Up To Another
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