Question 32498
1) No.  sqrt(-3)^2 = sqrt(9)=3
2) x-sqrt x = 0
   x = sqrtx
Square both sides to get:
x^2=x
x^2-x=0
x(x-1)=0
x=0 or x=1
Check the solutions in the original equation
Checking x=0: 0-sqrt0=0   OK
Checking x=1: 1-sqrt1=0   OK
3)  I'll leave this to you to graph.
Cheers,
Stan H.