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What is the solution set of x2 + 5x -5=0

User RToyo
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1 Answer

25 votes
25 votes

Explanation:

x² + 5x - 5 = 0

the general solution to such a quadratic equation is

x = (-b ± sqrt(b² - 4ac))/(2a)

in our case

a = 1

b = 5

c = -5

x = (-5 ± sqrt(25 - 4×1×-5))/(2×1) =

= (-5 ± sqrt(25 + 20))/2 = (-5 ± sqrt(45))/2 =

= (-5 ± sqrt(9×5))/2 = (-5 ± 3×sqrt(5))/2

x1 = (-5 + 3×sqrt(5))/2 = 0.854101966...

x2 = (-5 - 3×sqrt(5))/2 = -5.854101966...

the solution set is {x1, x2}

User Vas Giatilis
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