In 1926 the very dirt first test asked if a mans salary is 20 dollars a week and he spends 14 dollars a week how long will it take him to save 300 dollars

It is a solve for x equation. It is written as 300=x (20-14) first you do the subtraction in the brackets 300=x (6) then divide both sides by 6 to find x 50=x it would take 50 weeks for him to save 300$ (feel free to check that by putting 50 in for x and solving)