So 7 friends with similar. Phone plans. 3 of them pays an extra 4 bucks, so that means that x+ 4 is what 3 of the 7 r paying. The other 4 pay just x Amt of money for their plan. So go find the total bill, it would be (x+4)+(x+4)+(x+4)+x+x+x+x. Now simplify, (x+4)^3, because there are three of the 7 using that, and then x^4, because 4 of the 7 r using that plan. So in total it would be (x+4)^3+ x^4. Hope this helps
