A sample of a radioactive isotope had an initial mass of 120 mg in the year 2010 and decays exponentially over time. A measurement in the year 2015 found that the
sample's mass had decayed to 50 mg. What would be the expected mass of the sample
in the year 2018, to the nearest whole number?

its definatley   this on your answer choice?

x=-7

step-by-step explanation:

x+3=-10

-10+3=-7

x=-7

answer: - (a)

(b) 88 seats

step-by-step explanation:

given: in an auditorium, there are 22 seats in the first row and 28 seats in the second row.

thus first term=

second term=

the number of seats in a row continues to increase by 6 with each additional row.

⇒d= 6

a) given formula :

b)   let the number of seats (n) = 12

substitute n=12 in the explicit rule formed in (a)

∴there are 88 seats in 12 rows.