Which expressions are equivalent to 4m - 2 + (-8m)

Element x decays radioactively with a half life of 8 minutes. if there are 450 grams of element x, how long, to the nearest tenth of a minute, would it take the element to decay to 37 grams?

One positive number is 9 more than twice another. if their product is 95, find the numbers

How long must $542 be invested at a rate of 7% to earn $303.52 in interest? in a easier way