The half-life of a radioactive isotope is the time it takes for a quantity of the Isotope to be reduced to half its initial mass. Starting with 210 grams of a radioactive isotope, how much will be left after 6 half-lives?
Round your answer to the nearest gram

after 6 half lives: 210(1/2)^6= 3.28125

Step-by-step explanation:

isotope to be reduced to half its initial mass at first:

210(1/2)=105 half it is original weight

after second life: 210(1/2)^2=105(1/2)=52.5

after third : 210(1/2)^3=52.5/2=26.25

after fourth : 26.25/2=12.125

after fifth : 13.125/2

after 6 half lives: 210(1/2)^6= 3.28125

hello from mrbilldoesmath!

answer:   (7x + 6y) ( 49x^2 - 42xy + 36y^2)

discussion:

in general, the factorization of a^3 + b^3 is

a^3 + b^ 3 = (a + b) ( a^2 - ab + b^2)

in our case note that 343 = 7^3 and 216 = 6^3 so the equation becomes:

343x^3 + 216y^3 = (7x)^3 + (6y)^3

if you think of a (above) as 7x and b as 6y the factorization becomes

343x^3 + 216y^3 =

((7x + 6y) (   (7x)^2 - 7x*6y + (6y)^2)   =

(7x + 6y) ( 49x^2 - 42xy + 36y^2)

you,

mrb

(a + b) (a^2 - a b + b^2)