Answer:
xy=4 AND
y=7x^4
Explanation:
B. xy = 4 is a hyperbola, which is a two-piece curve with an asymptote.
C. y = 7x^4
is a quartic, also a curve.
You can tell the other equations ARE linear, because they have no exponent on the variables. (If you solve the "xy" equation for y, the x ends up on the bottom of a rational expression--not linear)