How can you find the independent variable and the dependent variable given a situation

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?

Is this a polynomial function? i need to know asap

If abcde is reflected over the x-axis and then translated 3 units left, what are the new coordinates d?