Answer:
b. -x + y = 0
Explanation:
Direct variation:
Direct variation means "y varies directly as x”:
where k is the (non-zero) constant of variation.
To determine which of the given equations represents a direct variation, isolate y for each and compare with the direct variation equation.
Equation a
This is not a direct variation equation as there is an addition of -2.
Equation b
This is a direct variation equation where the constant of variation is 1.
Equation c
This is not a direct variation equation as y is inversely proportional to x.
Equation d
This equation does not include the variable x, and so is therefore not a direct variation equation.