SOLUTION: Find all solutions: 2cos^2 x + cos x = 1 Please explain Thank you

Question 920590: Find all solutions:
2cos^2 x + cos x = 1
Please explain
Thank you
Found 2 solutions by ewatrrr, stanbon:
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!
2cos^2 x + cos x - 1 = 0
(2cos x -1)(cos x + 1) = 0
cos x = 1/2, x = π/3 + n(2pi)
or
cos x = -1, x = π + n(2pi)
...........
(cosx, sinx) Summary Unit Circle
.

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Find all solutions:
2cos^2 x + cos x = 1
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2cos^2(x) + cos(x) - 1 = 0
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Factor::
(2cos(x)-1)(cos(x)+1) = 0
cos(x) = 1/2 or cos(x) = -1
---
x = +/-pi/3 or x = pi
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Cheers,
Stan H.
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