<PRE><B>Question 273332</B>
My Textbook gives a sample hyperbola equation 
(x^2 / 9) - (y^2 / 16) = 1 
It then has 
y = ą(4/3)&amp;#8730;x^2 - 9 
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(x^2/9) - (y^2/16) = 1
Multiply thru by 144 to get:
16x^2 - 9y^2 = 144
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Rearrange:
9y^2 = 16x^2-144
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Divide thru by 9 to get:
y^2 = (16/9)x^2 - 16
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y = +/- sqrt(16/9)x^2 - 16)
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Factor out the 16
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y = +/-4sqrt((1/9)x^2 - 1)
y = +/-4sqrt[(1/9)(x^2 - 9)]
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Bring out the (1/9)
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y = +/-(4/3)sqrt(x^2 - 9)
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Cheers,
Stan H.</PRE>