5x - 2x = 63 + 57
3x = 120
x = 40
The second bubble is the answer
Answer:
M = 1/0.000121 = 8264.5 years
Step-by-step explanation:
M = − k ∫∞₀ teᵏᵗdt
To obtain this mean life, we'll use integration by parts to integrate the function ∫ teᵏᵗdt
∫udv = uv - ∫ vdu
u = t
du/dt = 1
du = dt
∫ dv = ∫ eᵏᵗdt
v = eᵏᵗ/k
∫udv = ∫ teᵏᵗdt
uv = teᵏᵗ/k
∫ vdu = eᵏᵗ/k
∫ teᵏᵗdt = (teᵏᵗ/k) - ∫eᵏᵗ/k
But, ∫eᵏᵗ/k = (1/k) ∫eᵏᵗ = (1/k²) eᵏᵗ = eᵏᵗ/k²
∫ teᵏᵗdt = (teᵏᵗ/k) - eᵏᵗ/k²
The rest of the calculation is done on paper in the image attached to this question
Answer:
Please see the attached file for the complete answer.
Step-by-step explanation: