We have to cross 1 over to the other side so that x becomes a value on its own. Because we are it over, the addition sign changes to subtraction which makes the expression,
x2 = 9- 1
x2 = 8
For x to stand alone we have to divide both sides by 2
Allen has already run 3 hours and will run x amount more to finish. This is 3+x. He must finish under or less than 5.5 hours. So 3 + x < 5.5. You solve and find x < 2.5.