Eliminate the parameter x = abs(t-3) and y = t + 3...how do you undo the absolute value in order to get y=?

well I suppose x^2 = t^2 -6 t + 9

for x = t-3 and for x = 3-t
but t = y-3
t^2 = y^2-6y+9
so
x^2 = y^2-6y+9 -6(y-3) + 9
x^2 = y^2 + 36
y^2 = x^2-36
y = (x^2-36)^.5