Question 585171
(x^2+20xy+100y^2)z^2-16(x^2+20xy+100y^2)
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(x+10y)^2*z^2-16(x+10y)^2
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= (x+10y)^2[z^2-16)
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= (x+10y)^2(z-4)(z+4)
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Cheers,
Stan H.