If LN is 13x-10,LM is 32 and MN is 6x-11 then LN is how many units long

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?

Pls the last one and it has to be like number 6

Which number is located at point a on the number line? a number line is shown from negative 10 to 10 with each interval mark on the number line representing one unit. point a is labeled one interval mark to the right of negative 5.