Answer:
A = NO
B = NO
C = YES
D = YES
Explanation:
A linear equation is an equation of a straight line, which means that the degree of a linear equation must be 0 or 1 for each of its variables.
For A: The degree of variable y is 1 and the degree of variable x is 2.
So it is not linear.
For C: The degree of variable y is 1 and the degree of variable x is 1.
So it is linear.