What are the inequalities for a slope of 1/2 and a y intercept of -2

Initially 100 milligrams of a radioactive substance was present. after 6 hours the mass had decreased by 4%. if the rate of decay is proportional to the amount of the substance present at time t, find the amount remaining after 24 hours. (round your answer to one decimal place.)

What is the best reason for jacinta to have a savings account in addition to a checking account

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?