15-b=4b-5(5-3)
Multiply the bracket by -5
(-5)(5)=-25
(-5)(-3)=15
15-b=4b-25+15
15-b=4b-10
Move 15 to the other side
Sign changes from +15 to -15
15-15-b=4b-10-15
-b=4b-25
Move 4b to the other side.
-b-4b=4b-4b-25
-b-4b=-25
-5b=-25
divide both sides by -5
-5b/-5=-25/-5
Answer: b=5
F=ar^t if the half-life is 96 years...
.5=r^96
ln(.5)=96lnr
ln(.5)/96=lnr
r=e^((ln.5)/96)
f=800e^(336(ln.5)/96)
f=70.71
So about 71mg will remain after 336 years.
The list is long, but here goes:
10/12, 15/18, 20/24, 25/30, 30/36, ... and so on.
Answer:
6.35
Explanation:
7 divided by 20 is 0.35+6= 6.35
Tan inverse 3/5 is 30.96
so the answer is x = 31.0
