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Find all rational zeros of P(x) = x3 - 7x + 6. 
 

 Dec 7, 2015
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Solve for x:
x^3-7 x+6 = 0

The left hand side factors into a product with three terms:
(x-2) (x-1) (x+3) = 0

Split into three equations:
x-2 = 0 or x-1 = 0 or x+3 = 0

Add 2 to both sides:
x = 2 or x-1 = 0 or x+3 = 0

Add 1 to both sides:
x = 2 or x = 1 or x+3 = 0

Subtract 3 from both sides:
Answer: | x = 2    or x = 1    or x = -3
 

 Dec 7, 2015

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