You should write a 1 because I f what you add is 11, 12, 13, 14, 15, 16, 17, 18, or 19 there is a 1 in the front of the numbers so you must put a 1 but if the number was 76 the number in the front is 7 so you would put 7 on the tens column.
Undo what has been done to the variable. That means to do the opposite done to the variable. 5x-4=-19 +4=+4 5x=-15 5 is being multiplied to the variable so you divide it from both sides. x=-3
