SOLUTION: 8x^(4)-6x^(2)-5=0

Question 204232: 8x^(4)-6x^(2)-5=0
Found 2 solutions by Earlsdon, stanbon:
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
SOlve for x:
You can expect to get four solutions to this "quartic" equation. First, rewrite the equation so as to appear like a "quadratic" equation in :
Factor this "quadratic"equation.
Apply the zero product rule:
or so that...
or and...
or Now take the square root of both sides of these two intermdediate solutions.
or or
or
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
8x^(4)-6x^(2)-5=0
-----------------------
Factor the left side:
8x^4 - 10x^2 + 4x^2 - 5 = 0
Factor the 1st 2 and the last two terms separately to get:
2x^2(4x^2-5)+ (4x^2-5) = 0
(4x^2-5)(2x^2+1) = 0
Solve for "x":
4x^2 = 5 or 2x^2+1 = 0
x^2 = 5/4 or x^2 = -1/2
x = +/-sqrt(5/4) or x = +-isqrt(1/2)
=========================================
Cheers,
Stan H.
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