The number of real roots of the polynomial equation $x^4-x^2+2 x-1=0$ is

Solution of the equation $\sqrt {x + 3 - 4\sqrt {x - 1} }  + \sqrt {x + 8 - 6\sqrt {x - 1} }  = 1$ is

If $|{x^2} - x - 6| = x + 2$, then the values of $x$ are

If the inequality $kx^2 -2x + k \geq  0$ holds good for atleast one real $'x'$ , then the complete set of values of $'k'$ is

Let $x_1, x_2, \ldots, x_6$ be the roots of the polynomial equation $x^6+2 x^5+4 x^4+8 x^3+16 x^2+32 x+64=0$. Then,

The real roots of the equation ${x^2} + 5|x| + \,\,4 = 0$ are