...Therefore, any number less than 1 would
make x + 3 > 4 untrue. x a little greater than 1 makes x + 3 a little more than 4. Therefore, any number greater than 1 would make x + 3 > 4 true. And we have the solution: {x: x > 1} satisifies the inequality x + 3 > 4. (read more)