SOLUTION: Solve: (2t + 1)^3 = (2t + 1) My solution: (2t + 1)^3 / (2t + 1) = (2t + 1) / (2t + 1) (2t + 1)^2 = 1 4t^2 + 4t + 1 = 1 4t^2 + 4t = 0 4t (t + 1) = 0 t = 0 or t =

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Solve: (2t + 1)^3 = (2t + 1) My solution: (2t + 1)^3 / (2t + 1) = (2t + 1) / (2t + 1) (2t + 1)^2 = 1 4t^2 + 4t + 1 = 1 4t^2 + 4t = 0 4t (t + 1) = 0 t = 0 or t =      Log On


   

Question 887238: Solve: (2t + 1)^3 = (2t + 1)
My solution:
(2t + 1)^3 / (2t + 1) = (2t + 1) / (2t + 1)
(2t + 1)^2 = 1
4t^2 + 4t + 1 = 1
4t^2 + 4t = 0
4t (t + 1) = 0
t = 0 or t = -1
But the book gives a third possibility: t = -1/2
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
(2t + 1)^3 = (2t + 1)
(2t + 1)^3 - (2t + 1)=0
(2t + 1)^3 -(2t + 1)
(2t + 1)*((2t + 1)^2-1)=0
(2t + 1)=0
2t=-1
t=-1/2
(2t + 1)^2-1=0
(2t + 1)^2=1
2t+1=+-1
2t=0
t=0
2t=-2
t=-1
another way
(2t + 1)^3 = (2t + 1)
8t^3+12t^2+6t+1=2t+1
8t^3+12t^2+4t=0
4t*(2t^2+3t+1)=0
4t=0
t=0
(2t^2+3t+1)=0
(t+1) (2t+1) = 0
t=-1
t=-1/2