SOLUTION: I need some help with this problem please : 5x^2 + 12x = -9 A x = (-6 +- 3i)/5 B x = (6 +- -3i)/5 C x = (3 +- 6i)/12 D x = (3 +- 6i)/5 E x = (-3 +- 6i)/5 F x = (-9 +- 12i

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: I need some help with this problem please : 5x^2 + 12x = -9 A x = (-6 +- 3i)/5 B x = (6 +- -3i)/5 C x = (3 +- 6i)/12 D x = (3 +- 6i)/5 E x = (-3 +- 6i)/5 F x = (-9 +- 12i      Log On


   

Question 326366: I need some help with this problem please :
5x^2 + 12x = -9
A x = (-6 +- 3i)/5
B x = (6 +- -3i)/5
C x = (3 +- 6i)/12
D x = (3 +- 6i)/5
E x = (-3 +- 6i)/5
F x = (-9 +- 12i)/5
Any help would be much appreciated !!!
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
5x^2 + 12x = -9
5x^2 + 12x + 9 = 0
a = 5 ; b = 12 ; c = 9
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x = [-b +- sqrt(b^2 - 4ac)]/(2a)
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x = [-12 +- sqrt(144 -4*5*9)]/(10)
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x = [-12 +- sqrt(-36)]/10
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x = [-12 +- 6i]/10
---
x = [-6 +-3i]/5
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Cheers,
Stan H.
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A x = (-6 +- 3i)/5
B x = (6 +- -3i)/5
C x = (3 +- 6i)/12
D x = (3 +- 6i)/5
E x = (-3 +- 6i)/5
F x = (-9 +- 12i)/5