Answer:
y = (x - 5)² - 2
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k) = (5, - 2), thus
y = a(x - 5)² - 2
To find a substitute (7, 0) into the equation
0 = a(7 - 5)² - 2
0 = 4a - 2 ( add 2 to both sides )
2 = 4a ( divide both sides by 4 )
a = =
y = (x - 5)² - 2 ← in vertex form
Answer:
The mass of the radioactive sample after 40 minutes is 12.8 g.
Step-by-step explanation:
The mass of the sample can be found by using the exponential decay equation:
Where:
N(t): is the amount of the sample at time t =?
N₀: is the initial quantity of the sample = 120 g
t = 40 min
λ: is the decay constant = 0.056 min⁻¹
Hence, the mass of the sample after 40 min is:
Therefore, the mass of the radioactive sample after 40 minutes is 12.8 g.
I hope it helps you!