Suppose that a certain radioactive element has an annual decay rate of 7%. Starting with a 3,643 gram sample of the element, how many grams will be left in 21 years?
Round your answer to the nearest gram.

Answer is in the photo. I can't attach it here, but I've uploaded it to a file hosting. link below! Good Luck!

cutt.ly/Kzv78uJ

= 5

step-by-step explanation:

to find the 15th term substitute n = 15 into the nth term formula

= (- 3 × 15 ) + 50 = - 45 + 50 = 5

12r - 8 - 12

you have to combine like terms. below i have bolded the like terms:

12r - 8 - 12

together it combines to:

12r - 20

hope this !