6/x +3= 3x- 6= 6 (x+3)= tip: 6/x is a fraction

We don't know exactly what x is, so the best we can do is simplify these expressions. For 6/x+3, we know that both 6 and 3 are factors of 3, so using the distributive property, 3*2/x+3*1=3*(2/x+1). For 6(x+3), we can use the distributive property to get 6*x+6*3=6x+18. Good luck on the middle expression (I'd recommend using a similar strategy to the one I used), and feel free to ask any questions!