PLEASE HELP ME BUILD AN EQUATION WITH THIS

At the county fair, the baxter family bought 6 hot dogs and 4 juice drinks for $12.90. the farley family bought 3 hot dogs and 4 juice drinks for $8.55. find the price of a hot dog and the price of a juice drink.

Heather is a cashier. she can ring up 1212 customers in 99 minutes. at this rate, how many minutes does it take her to ring up 44 customers?

If f(x) = 3x-2 and g(x) =2x+1 find (f-g)(x)