The numbers 1, -1 and a+1 are the roots of the equation x^3+6x^2-2bx-3c-12=0. Find the values of a,b, and c.
Put -1 in the equation
-1 + 6 + 2b- 3c -12 = 0
2b-3c = 7
Put 1 in the equation
1 + 6 - 2b-3c -12 = 0
-2b-3c = 5 Now you can solve for a and b (hint: add the two red equations)
See if you can find 'a' Hint (x-a-1) divided into the equation should leave no remainder....