How do you solve for the equation n/3+6=n

If x is 6, then 7x= a. 13 b. 42 c. 42x d. 76

Astore ordered 750 candles a total wholesale cost of $7910.20. the soy candles cosy $12.17 each and thespecialty candles cost $9.58each. how many of each were bought?

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /