Question 268967
Type an exact answer, using radicals as needed. Rationalize all denominators. use a comma to seperate answeres as needed. 
15x^4-8x^2+1=0
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Think of two numbers whose product is 1*15 = 15
and whose sum is -8.
The numbers are -5 and -3
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Change the middle term of your problem to -5x-3x
15x^2-5x-3x+1 = 0
Factor the 1st 2 and the last two terms separately:
5x(3x-1)-(3x-1) = 0
Factor again:
(3x-1)(5x-1) = 0
Solve for "x":
x = 1/3 or x = 1/5
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cheers,
Stan H.