Find the domain and range and describe the level curves for the function f(x,y).f(x, y) = ln (9x + 3y)

Question

A. Domain: all points in the xy-plane satisfying 9x + 3y > 0; range: all real numbers; level curves: lines 
B. Domain: all points in the xy-plane satisfying 9x + 3y > 0; range: real numbers z ? 0; level curves: lines 
C. Domain: all points in the xy-plane satisfying 9x + 3y ? 0; range: all real numbers; level curves: lines 
D. Domain: all points in the xy-plane; range: all real numbers; level curves: lines 

Answer 1

Answer: A