Roni wants to write an equation to represent a proportional relationship that has a constant of proportionality equal to StartFraction 7 over 25 EndFraction. She writes the equation y = x + StartFraction 7 over 25 EndFraction. What error is Roni making? She should have written y = negative x + StartFraction 7 over 25 EndFraction so that x and y have a constant sum. She should have written x y = StartFraction 7 over 25 EndFraction so that x and y have a constant product. She should have written y = StartFraction 7 over 25 EndFraction x so that x and y have a constant quotient. She should have written y = StartFraction 7 over 25 EndFraction so that y has a constant value.