At a concession stand, five hot dogs and four hamburgers cost 11.00; four hot dogs and five hamburgers cost 11.50. find the cost of of one hot dog and the cost of one hamburger

Me! i really need to get this right before 9. prove the divisibility of 7^6+7^5-7^4 by 11. use factoring so you get a number times 11. just tell me the number. i need this done asap