Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
Answer:
y=0
Step-by-step explanation:
Answer:
3^9x=3^-2x
Step-by-step explanation:
27^3x=(1/9)^x
3^3×3x=(1/3^2)^x
3^9x=3^-2x
Answer:
y = -2x + 4
Step-by-step explanation:
y = -2x + b
-8 = -2(6) + b
-8 = -12 + b
4 = b
Answer:
y = -3/2x + 5/2
Step-by-step explanation:
Point: (5, -5)
Parallel to: y = -3/2x + 2
Slope= -3/2 (parallel lines have the same slope)
y-intercept = -5 - (-3/2)(5) (y - slope times x) =
-5 + 15/2 = 5/2
