Answer:

Step-by-step explanation:
Given:
The expression to expand is given as:

Let us expand the first two binomials of the given expression using FOIL method.
The FOIL method states that:


Now, let us multiply the result with the remaining binomial. Multiplying each term of the trinomial with each term of the binomial, we get:

Therefore, the equivalent expression after expanding is given as:

Answer: 
Step-by-step explanation:

Distribute the negative sign. This basically changes all the signs inside the parentheses.

Combine like terms;

For a half- life, the formula is
A(t) = A0(0.5)^( t / t_0.5)
where A(t) is the amount of substance at time t
A0 is the initial amount of subtance
t_0.5 is the time it will reduce its amount to half
t is the time
substitute the given to the formula
A(t) = 100(0.5)^( t/6 )
so the decay factor is 0.5^( t/6 )