Question 366877
7(x+4)-10=3x+20+4x-2 
7x+28-10 = 7x+18
7x + 18 = 7x+18, ultimately
0 = 0.
What does this mean, my dear STUDENT?  Obviously 0 = 0 is an irrefutably true statement (unless your number system is different from ours, hehe.)  It means whatever real value you put in for x will always lead you to 0 = 0, which means the solution set is the set of ALL real numbers, which, you know, has infinitely many elements.