Someone and explain the first one so the half life of a radioactive kind of potassium is 12 hrs . how much will be left after 36 hrs, if you start with 64 grams of it? so i did a=64(1/2)^36 power is that the accurate form i need asap
btw this is exponential decay

Don't get carried away with the exponent.

The exponent is not the number of years or the number of hours.
The exponent is the number of half-lifes.

In this one, the half-life is 12 hours, and they want to know
how much is left after 36 hours.  36 hours is 3 half-lifes.
The formula that you did is beautiful and almost perfect.
Just change that ugly exponent to the number of half-lifes (3)
and the answer will jump out at you.

Half life formula is
F=P(1/2)^(t/h)

F=furure or ending amount
P=present amount
t=time elapsed
h=time the half life is

F=64(1/2)^(36/12)
F=64(1/2)^(3)
F=64(1/8)
F=8 grams