I assume that this is a polynomial:
Domain: all x in Real Numbers
Range: Will need to look at end point behavior and min/max. We'll answer after we determine that information
End Point Behavior: The lead term determines the behavior as x goes to +/- infinity. The x^6 term will go to + infinity in both cases, so the upper bound on P(x) is infinite.
y-intercept is easy: just constant term (x=0) y(0) = -6
zeroes: 1 works. There is another real zero and 2 sets of complex conjugates
Minimum: You can take the derivative and find the real zero at (-1,-8) with -8 being the min of y, so y ∈ [-8,∞)
Otherwise, plot the function on Desmos or use Wolfram Alpha to find roots.