Can someone help me please?

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?

The candy store is having a 30% off sale. emma is going to buy $7.50 worth of candy. how much will she pay after the discount