Would 2/5x+6/5=y be a proper answer format(i just want to know if it can be =y)

yes, it does not matter if the y is at the beginning or at the end. However, most teachers usually prefer to have the y at the beginning as it is easier to read.

this linear equation would have just one solution.

step-by-step explanation:

the reason why this would have one solution is that it is an expression with just one variable. since that variable is not raised to a power, it will always have just one solution.