Final answer:
Equation c. y=x²+6 does not belong because it is a quadratic equation, while the others are linear equations.
Step-by-step explanation:
The equation that does not belong with the other three is c. y=x²+6. The reason for this is that equations a. y=0.5x−0.2, b. 4x+3=y, and d. (3/4)x+(1/3)=y are all linear equations, which can be written in the form y = mx + b, where m is the slope and b is the y-intercept. However, equation c represents a quadratic equation, which is characterized by the x² term and results in a parabolic graph, not a straight line.