How do I solve these problems?

A radioactive substance decays in such a way that the amount of mass remaining after t days is given by the function m(t) = 12e-0.017t where m(t) is measured in kilograms. (a) Find the mass at time t = 0. kg (b) How much of the mass remains after 49 days? (Round your answer to one decimal place.) kg 2. Question Details SPreCalc7Coreq 4.3.035.MI. [4294903] Use the definition of the logarithmic function to find x. (Simplify your answer completely.) (a) log3(x) = 4 X = (b) log10(0.0001) = x X= 3. Question Details SPreCalc7Coreq 4.5.039.MI. [4294848] Solve the equation. (Enter your answers as a comma-separated list. Round your answers to four decimal places.) e2x - 9ex + 8 = 0 X = Question Details SPreCalc7Coreq 4.5.063. [4295251] Solve the logarithmic equation for x. (Enter your answers as a comma-separated list.) log2(x) + 1092(x - 7) = 3 X=