Answer:
the answer is 7.2 10³
Step-by-step explanation:
7.2 10³
Answer: 18x^3-9x^2+21x
Solution:
3x(6x^2-3x+7)=
Applying the distributive property in the multiplication to eliminate the parentheses:
(3x)(6x^2)+(3x)(-3x)+(3x)(7)=
(3*6)x^(1+2)+3*(-3)x^(1+1)+(3*7)x=
18x^3-9x^2+21x
Which equations? I think you forgot to post a picture.
Answer:
the question is incomplete, so I looked for a similar one:
<em>After the release of radioactive material into the atmosphere from a nuclear power plant, the hay was contaminated by iodine 131 ( half-life, 8 days). If it is all right to feed the hay to cows when 10% of the iodine 131 remains, how long did the farmers need to wait to use this hay? </em>
iodine's half life (we are given x, we need to find b):
0.5A₀ = A₀eᵇˣ
x = 8 days
we eliminate A₀ from both sides
0.5 = eᵇ⁸
ln 0.5 = ln eᵇ⁸
-0.69315 = b8
b = -0.69315 / 8 = -0.08664
since the farmers need to wait until only 10% of the iodine remains (we already calculated b, now we need to find x):
0.1A₀ = A₀eᵇˣ
0.1 = eᵇˣ
ln 0.1 = bx
where b = -0.08664
x = ln 0.1 / -0.08664 = -2.302585 / -0.08664 = 26.58 days
