Answer:
Amount of Niobium-91 initially
= 300/91 =3.2967mol
2040 years = 3 ×680 = 3 half-lives
therefore, amount left = 0.4121mol
mass of Niobium-91 remaining = 0.4121 ×91 =37.5g
Please give brainliest
If it was one year it would be 2200 and you just keep adding 200 for each year.
Answer:
f(x)=x/7
Step-by-step explanation:
f(x)=7x
y=7x
x=7y (switch y and x for inverse)
x=7y (isolate y)
x/7=y
The inverse of f(x)=7x is f(x)=x/7
Answer:
x = sqrt(3)/5 - 9/5 or x = -9/5 - sqrt(3)/5
Step-by-step explanation by completing the square:
Solve for x over the real numbers:
4 (5 x + 9)^2 - 33 = -21
Add 33 to both sides:
4 (5 x + 9)^2 = 12
Divide both sides by 4:
(5 x + 9)^2 = 3
Take the square root of both sides:
5 x + 9 = sqrt(3) or 5 x + 9 = -sqrt(3)
Subtract 9 from both sides:
5 x = sqrt(3) - 9 or 5 x + 9 = -sqrt(3)
Divide both sides by 5:
x = sqrt(3)/5 - 9/5 or 5 x + 9 = -sqrt(3)
Subtract 9 from both sides:
x = sqrt(3)/5 - 9/5 or 5 x = -9 - sqrt(3)
Divide both sides by 5:
Answer: x = sqrt(3)/5 - 9/5 or x = -9/5 - sqrt(3)/5
