When will the roots of x2 - 4x - log2x = 0 be real.
For the roots to be real, the discriminant of the quadratic formula must be >= 0.
b2 - 4·a·c >= 0 ---> (-4)2 - 4·1·log2(A) >= 0
16 - 4·log2(A) >= 0
- 4·log2(A) >= 16
log2(A) >= -4
A >= 2-4
A >= 1/16