Answer:
Step-by-step explanation:
1. (2/z)x^2 + (3/z)y^2 is an equation for an ellipse, so the answeris A.
2. We can rewrite this as x^2 + y^2 = 25 - z^2. This is theequation for a circle, so the level curves are circles. However,they are unevenly spaced, because the radius of each circle issqrt(25-z^2). So the answer is F.
3. Rewriting, we have y = z/x. This is the equation of a hyperbola(except when z = 0). So the answer is B.
4. Rewriting, we have x^2 + y^2 = z^2. This is the equation for acircle of radius z, so the level curves are evenly spaced circles.The answer is C.
5. Solving for x, we have x = 1 + 1/z. These level curves arevertical lines, which are obviously parallel. However, they areunequally spaced, since the distance between them gets smaller as zgets larger. The answer is E.
6. x^2 + y^2 = z is the equation for a circle of radius sqrt(z).They are unevenly spaced once again, because the radii do notincrease linearly with z. The answer is F.
7. Solving for y gives: y = (-2/3)x + z/3. This is the equation fora line of slope -2/3 with y-intercept z/3. These are parallelbecause they all have the same slope, and evenly-spaced becauseeach time we increase z by 1 the y-intercept moves up by 1/3. Theanswer is D.
