Question 321190
express using positive exponent
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Comment: When there is a negative in the exponent, it 
means "invert".
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b^-4 = 1/b^4
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multiply
(w+d)(w^2-wd+d^2)
= w(w^2-wd+d^2) + d(w^2-wd+d^2)
= w^3-w^2d+wd^2 + w^2d - wd^2 + d^3
= w^3 + d^3
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(-3x)^2(4x^6)^2
= (9x^2)(16x^12)
= 144x^14
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solve
15x^4 -31x^2 +10=0
Factor:
(3x^2-5)(5x^2-2) = 0
x = +-(5/3) or x = +-(2/5)
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(x+14)(x-10)(x+1)>0 
Draw a number line and plot the boundary points
x = -14, x= -1, x = 10
Pick a check point in each of the 4 resulting intervals
to see where the solutions for the INEQUALITY lie.
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Checking x= -20 you get: -*-*- >0 false
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Checking x = -10 you get: +*-*- >0 true
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Checking x = 5 you get: +*-*+ >0 false
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Checking x = 20 you get: +*+*+ > 0 true
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Solutions in (-inf,-14)U(-1,10)
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subtract the polynomial
(-4s^2 +9s+2)-(8s^2+2)
= -12s^2 + 9s 
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cheers,
Stan H.