SOLUTION: Solve f(x) = (x^3) - (6x^2) + 7x + 2 = 0

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve f(x) = (x^3) - (6x^2) + 7x + 2 = 0      Log On


   



Question 365580: Solve f(x) = (x^3) - (6x^2) + 7x + 2 = 0
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi,
Note: exploring factor of the constant term 2, found that x = 2 is a root
f(2) = 8 - 24 + 14 + 2 = 0
x^2 - 4x -1
__________________________
x - 2 | x^3 - 6x^2 + 7x + 2
- (x^3 - 2x^2
---------------
-4x^2 + 7x
- (-4x^2 + 8x )
---------
-x + 2
- (-x + 2)
--------
0

x^2 - 4x -1
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%284+%2B-+sqrt%2820%29%29%2F%282%29+
x+=+%284+%2B-+sqrt%284%2A5%29%29%2F%282%29+
x+=+%284+%2B-+2sqrt%285%29%29%2F%282%29+
+x=+2+%2B-+sqrt%285%29