Elisa middle school im a student x + 5 + x, if x = 4 Hi Elisa, To do this type of problem you simply "substitute" the number 4 everywhere you see an "x" in the question and then do the operations. In other words, change the x's to 4's and,in this case, add them up. So x + 5 + x if x=4 becomes 4 + 5 + 4 which equals 13. Hope this helps, Leeanne
