Answer:
x=1 y=4
Step-by-step explanation:
The amount of substance left of a radioactive element of half life,

after a time, t, is given by:

Given that <span>potassium-40 has a half life of approximately 1.25 billion
years.
The number of years it will take for 0.1% of potassium-40 to remain is obtained as follows:

Therefore, </span><span>the maximum age of a fossil that we could date using 40k is
12.5 billion years.</span>
Answer:
4/3 or 1.3333333...
Step-by-step explanation:
2 x (3x + 1)-4 = 6.
6x+2-4=6.
6x+2=10
6x=8.
X= 1.3333333... OR 4/3
Answer:
Step-by-step explanation:
7(x-5)²=63
(x-5)²=63/7
(x-5) = +/- 3
x = 5 + 3
or
x = 5- 3
x = 8 or 2