Ni : Zn: Cu = 7:2:9 =7x : 2x : 9x
7x+2x+9x = 3.8
18x=3.8
x=3.8/18=1.9/9≈0.21
Ni: 7x=7*0.21=1.47 ≈1.5 kg
Zn: 2x=2*0.21=0.42≈0.4 kg
Cu: 9x=9*0.21=1.89 ≈1.9 kg
Check 1.5+0.4+1.9 =3.8 True
Answer: 
Step-by-step explanation:
We know that the general form of the exponential decay formula is
, where y is final amount remaining after t time, A is the original amount and r is the rate of decay
Now, the ratio of strontium-90 remaining, p , as a function of years, t , since the nuclear accident. 
Hence, the ratio of remaining since the nuclear accident is 
Answer:
2
Step-by-step explanation:
hope this helps
Answer:
(x-4)(3x+2)
Step-by-step explanation:
Hi!
So the original formula for a problem likes this or a quadratic is:
ax^2 + bx+ c
so a is the accelaration; b is the initial velocity; and c is the initial height
so none of those are the zeros, which means c is out
zeros are the x values when y is 0, that also means when the parabola crosses the x axis
so d is out too because the maximum height is the vertex which mean that there would probably be a y value. in some cases the vertex is the zero, but not here
B is out because x isn't time it is distance
your answer is A!
Hope this helps!