You were planning to spend $12 on a pizza. write and solve an inequality to represent the additional amount you must spend to get free delivery.
free delivery — for orders of $30.00 or more

You have $12, and need at least x more dollars to spend $30 total. So the inequality is 12 + x ≥ 30, where x is the number of dollars needed to get free delivery. To solve for x, subtract 12 from each side of the sign. x ≥ 30 - 12, x ≥ 18. You must spend at least 18 more dollars to qualify for free delivery.