Work out the value of x, 2x + 9, x + 13, x - 8

If f(x)= 3x+6 which of the following is the inverse of f(x)

Someone this asap for a group of students attends a basketball game. * the group buys x hot dogs at the concession stand for $2 each. * the group buys y drinks at the concession stand for $3 each. the group buys 29 items at the concession stand for a total of $70. how many hot dogs did the group buy?

Ineed i been stuck on this question since yesterday