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
We can automatically see that we are dealing with a percent decrease because we are going from a smaller to a bigger number. We need to first find what percent of 140the number 84 is. to do this we can set up the following equation:
140/84=100/x (this equation is basically saying if 140 is 100(%) what would 84 be?)
solving for x here gives us x = (84 X 100)/140 = 60, so 84 is 60 percent of 140 which means 140 decreased by 40 percent.
Let me know if I can clear anything else up.
I hope this helps. X is equal to 4 and -9