4) -0.3 = -1/3 < -1/7 since the bigger a negative number is the less positive it is. 1/8 is positive so it is clear that it should be placed last. & thus do all options this way.
Eduardo put $40 in so the 40 is what he has already put in. Next you have $5 added in but it doesn’t say for how many months just that it’s each month so we put the x to represent out unknown so we can solve the equation.