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What two numbers multiply to get -8 and add to get 4?

User Sergii Dymchenko
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1 Answer

13 votes
13 votes

Answer:

-2-2√3, -2+2√3

Explanation:

Let x and y be two numbers.

Let x represent one of the numbers. Then the other number is -4-x. We want the product to be -8:

x(-4-x) = -8

-4x -x^2 = -8 . . . . . eliminate parentheses

x^2 +4x = 8 . . . . . . multiply by -1

x^2 +4x +4 = 12 . . . add 4 to complete the square

(x +2)^2 = 12

x +2 = ±√12 = ±2√3

x = -2±2√3

User Giffary
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