Answer:
0.75 mg
Step-by-step explanation:
From the question given above the following data were obtained:
Original amount (N₀) = 1.5 mg
Half-life (t₁/₂) = 6 years
Time (t) = 6 years
Amount remaining (N) =.?
Next, we shall determine the number of half-lives that has elapse. This can be obtained as follow:
Half-life (t₁/₂) = 6 years
Time (t) = 6 years
Number of half-lives (n) =?
n = t / t₁/₂
n = 6/6
n = 1
Finally, we shall determine the amount of the sample remaining after 6 years (i.e 1 half-life) as follow:
Original amount (N₀) = 1.5 mg
Half-life (t₁/₂) = 6 years
Number of half-lives (n) = 1
Amount remaining (N) =.?
N = 1/2ⁿ × N₀
N = 1/2¹ × 1.5
N = 1/2 × 1.5
N = 0.5 × 1.5
N = 0.75 mg
Thus, 0.75 mg of the sample is remaining.
2 to the 12th power should be correct
Answer:
a = 1
b = -1
c = -2
Step-by-step explanation:
We reorder the equation in such way that let us see the usual
ax² + bx + c = 0
Then the original quation is:
-2 = - x + x² - 4 ⇒ 0 = 2 - x + x² - 4 ⇒ x² - x - 2 = 0
Now we are able by simply inspection to identify a, b . c comparing our equation with the general equation so :
a = 1
b = -1
c = -2
