<PRE><B>Question 647901</B>
simplify the expression: 
(12x^2y/3z^4)(-21x^2z^3/12y^2)
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1st: Simplify each fraction by canceling common factors:
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= (4x^2y/z^4)(-7x^2z^3/4y^2) 
2nd Cancel any factor common to a numerator and a denominator:
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= (1*x^2*1/z)(-7*x^2*1/(1*y)
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= (-7x^4)/(yz)
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Cheers,
Stan H.
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