Question 224807
{ (36z^2) / (5z^2 -30z+45)} {5z-(15/6z)}
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{ (36z^2) / [(5z-15)(z-3)] } { (30z^2 -15)/6z) }
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{ (36z^2) / [ (5z-15)(z-3) ] } { 15(z^2 -1) /6z }
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{ (6z*6z)/ [ (5(z-3))(z-3)] } { 3*5(z+1)(z-1)/6z}
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cancel  like  terms
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{6*3*z(z+1)(z-1)} / (z-3)(z-3)
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18 z(z^2 -1) / (z^2 -6z +9)
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18(z^3-z)/(z^2 -6z+9)
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(18z^3 -18z)/ (z^2 -6z +9)
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check,,,let  x=1,,in  both  answer  and  original,,, =0
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let  x=2,,,{ } = 108,,,,,ok