Answer:
N=10
Step-by-step explanation:
9514 1404 393
Answer:
Step-by-step explanation:
The general approach here is to choose a variable you want to eliminate, identify the coefficients of it, and use those to multiply the equations so adding the products will eliminate the variable.
Here, the coefficients of x are -1 and -3; the coefficients of y are 2 and 5. We often like to choose the set of coefficients that includes 1 or where the coefficients are related by an integer factor. These criteria suggest that we should use the coefficients -1 and -3. One of our multipliers must be the opposite of one of these coefficients. So, we choose for them to be -3 and +1.
That is, multiplying the first equation by -3 will make the x-coefficient be 3; multiplying the second equation by 1 will make the x-coefficient be -3. Adding these equations will then eliminate x terms.
(-3)(-x +2y = 12)
<u>+ </u><u>(1)</u><u>(-3x +5y =27)</u>
<u>gives</u> (3x -6y) +(-3x +5y) = -36 +27
which simplifies to the sum ...
0x -1y = -9
__
Dividing by the coefficient of y, we find y = 9. Substituting into the first equation, we have ...
-x +2(9) = 12)
x = 18-12 = 6
The solution is (x, y) = (6, 9).
Answer with Step-by-step explanation:
Since 1 mole of sand will contain Avagadro's Number of sand particles (by definition of 1 mole)
Thus we have
1 mole of sand =
sand particles
Thus in number of trillion sand particles we have no of trillion sand particles in 12 mole is
![\frac{6.022\times 10^{23}}{10^{12}}=6.022\times 10^{11}](https://tex.z-dn.net/?f=%5Cfrac%7B6.022%5Ctimes%2010%5E%7B23%7D%7D%7B10%5E%7B12%7D%7D%3D6.022%5Ctimes%2010%5E%7B11%7D)
Now since it is given that mass of 1 trillion sand particles is 1000 tonnes Thus the mass of
trillion sand particles is
![Mass=1000\times 6.022\times 10^{11}=6.022\times 10^{14}tonnes](https://tex.z-dn.net/?f=Mass%3D1000%5Ctimes%206.022%5Ctimes%2010%5E%7B11%7D%3D6.022%5Ctimes%2010%5E%7B14%7Dtonnes)
Part 2)
Since it is given that volume of 1 sand particle is
thus the volume of 1 mole of sand is volume of
sand particles
Thus volume of 1 mole is ![V=1.00\times 10^{-18}km^{3}\times 6.022\times 10^{23}=6.022\times 10^{5}km^{3}](https://tex.z-dn.net/?f=V%3D1.00%5Ctimes%2010%5E%7B-18%7Dkm%5E%7B3%7D%5Ctimes%206.022%5Ctimes%2010%5E%7B23%7D%3D6.022%5Ctimes%2010%5E%7B5%7Dkm%5E%7B3%7D)
Now since the Area of united states is ![A=3.6\times 10^{6}mile^{2}=5.8\times 10^{6}km^{2}](https://tex.z-dn.net/?f=A%3D3.6%5Ctimes%2010%5E%7B6%7Dmile%5E%7B2%7D%3D5.8%5Ctimes%2010%5E%7B6%7Dkm%5E%7B2%7D)
Thus the depth of the sand pile is
![Depth=\frac{Volume}{Area}=\frac{6.022\times 10^5}{5.8\times 10^6}=0.10387km=103.8meters](https://tex.z-dn.net/?f=Depth%3D%5Cfrac%7BVolume%7D%7BArea%7D%3D%5Cfrac%7B6.022%5Ctimes%2010%5E5%7D%7B5.8%5Ctimes%2010%5E6%7D%3D0.10387km%3D103.8meters)
Answer:
the value of c is 25
Step-by-step explanation:
b/2a= 10/2(1)= 10/2= 5
(5)^2 = 25
x^2 + 10x + 25 = (x + 5)^2
Answer:
answer should be 2
Step-by-step explanation:
2^2+14=18