Given equation is x3 + x2 - 2x - 1 = 0
Since only one time sign changes from going left side to right side.
So, only one real root is possible.
\(\because\) f(0) = -1 & f(-1) = -1 + 1 + 2 - 1 = 1 > 0, where f(x) = x3 + x2 - 2x - 1
\(\therefore\) f(0) f(-1) < 0
\(\therefore\) Root lies between 0 and -1.