21. Given that (15 io f (-5) de = -5, which of the following must be true? 0 5/ 2 f () dp = -25 O - J'sof (p) dp = 1 O -5 /2 f (p) dp = -5 O 5 fo f (p) dp = -5 O - J Bo f (p) dp = -2517. After 28 days, a radioactive substance has decayed to 39.1% of its original amount. After an additional 33 days, what percent of its original amount will it have decayed to? 14.350 12.928 9.696 O 4.098 13.5744. Which of the following is the solution to the differential equation dy = $ with the initial condition y(e) = -5? Oy= 3ln(x) - 10 Oy= 3ln(2) Oy= 31(2) +8 Oy= 3ln(x) + 10 Oy = 3ln() - 8