CAT 2003 | Question: 1-105

Question

The number of non-negative real roots of $2^x - x - 1 =0$ equals _______

• A. $0$
• B. $1$
• C. $2$
• D. $3$

Answer 1

x=0 and x= 1 are the real root of the equation
So answer is C.2

Answer 2

$2^{x}$ = x+1

Taking log$\log _{2}$ on both side, we get

x = $\log _{2}$(x+1)

x = $\log _{2}x*\log _{2}1$

x = 0

I am not sure correct me I m wrong