Question 226626
x^3 -3x^2 -4x +12 =0
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with  4  terms,  normally  try  grouping
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x^2 ( x-3) -4(x-3)=0
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(x^2 -4) ( x-3) = 0,,,,,now  factor  difference  of  2  squares
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(x+2)(x-2)(x-3)=0
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x= 2, -2, 3
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check,,,(2),,,(2)^3 -3(2)^2 -4(2) +12 =0
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8-12-8+12=0,,,,ok
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(-2),,,,(-2)^3 -3(-2)^2 -4(-2) +12 =0
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-8 -12 +8 +12 =0,,,,ok
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(3),,,,,,(3)^3 -3(3)^2 -4(3)+12 = 0
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27 -27 -12+12 = 0,,,,,ok
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