What two numbers multiply to -21 and add up to 4?

Here we answer the question: "What two numbers multiply to -21 and add up to 4?"

The answer to your question is:

-3 and 7

Below we illustrate and prove that -3 and 7 multiply to -21 and add up to 4:

-3 × 7 = -21
-3 + 7 = 4

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

x² + 4x - 21 = 0

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

(x - 3 ) (x + 7)

To summarize, since -3 and 7 multiply to -21 and add up 4, you know that the following is true:

x² + 4x - 21 = (x - 3 ) (x + 7)

Multiply To One Number and Add Up To Another
Did you find the information on this page useful? Here you can solve a similar problem.