229k views
1 vote
What are two numbers that add to -1 and multiply to -8

User Yenthe
by
5.9k points

1 Answer

5 votes

Answer:

(-1-√33)/2, (-1+√33)/2

Explanation:

If one of them is x, then it satisfies ...

x + -8/x = -1

x^2 -8 = -x . . . . . multiply by x

x^2 +x = 8 . . . . . add x+8

x^2 +x + 1/4 = 8+1/4 . . . . complete the square

(x +1/2)^2 = 33/4

x + 1/2 = ±(1/2)√33 . . . . . . take the square root

x = (-1/2)(1 ± √33) . . . . . . . subtract 1/2

The numbers are approximately ...

-3.37228, 2.37228

User Azimuth
by
6.6k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.