Answer:
y = -7 and x = -36
Step-by-step explanation:
x - 4y = -8
5y - 1 = x
→ Substitute 5y - 1 into x - 4y = -8
5y - 1 - 4y = -8
→ Simplify
y - 1 = -8
→ Add 1 to both sides
y = -7
→ Substitute y = -7 into 5y - 1
( 5 × -7 ) - 1 = -36
Answer:
Step-by-step explanation:
Sec B
1) 5p⁻³ = 8*5⁻²
p⁻³ = 2³*5⁻²/5
p⁻³ =2³*5⁻³ { 1/a^m = a^-m}
p⁻³ = 5⁻³ /2⁻³ {a^m = 1/a^-m}
p⁻³ = (5/2)⁻³
p= 5/2
2) 4x² = 81
x² = 81/4
x² = 9² /2²
x² =(9/2)²
x = 9/2
3) 9^x/3 =81
9^x/3 = 9^2
Comparing the powers, x/3 = 2
x = 2*3 =6
x = 6
You can compute both the mean and second moment directly using the density function; in this case, it's
Then the mean (first moment) is
![E[X]=\displaystyle\int_{-\infty}^\infty x\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x\,\mathrm dx=710](https://tex.z-dn.net/?f=E%5BX%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5C%2Cf_X%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cfrac1%7B80%7D%5Cint_%7B670%7D%5E%7B750%7Dx%5C%2C%5Cmathrm%20dx%3D710)
and the second moment is
![E[X^2]=\displaystyle\int_{-\infty}^\infty x^2\,f_X(x)\,\mathrm dx=\frac1{80}\int_{670}^{750}x^2\,\mathrm dx=\frac{1,513,900}3](https://tex.z-dn.net/?f=E%5BX%5E2%5D%3D%5Cdisplaystyle%5Cint_%7B-%5Cinfty%7D%5E%5Cinfty%20x%5E2%5C%2Cf_X%28x%29%5C%2C%5Cmathrm%20dx%3D%5Cfrac1%7B80%7D%5Cint_%7B670%7D%5E%7B750%7Dx%5E2%5C%2C%5Cmathrm%20dx%3D%5Cfrac%7B1%2C513%2C900%7D3)
The second moment is useful in finding the variance, which is given by
![V[X]=E[(X-E[X])^2]=E[X^2]-E[X]^2=\dfrac{1,513,900}3-710^2=\dfrac{1600}3](https://tex.z-dn.net/?f=V%5BX%5D%3DE%5B%28X-E%5BX%5D%29%5E2%5D%3DE%5BX%5E2%5D-E%5BX%5D%5E2%3D%5Cdfrac%7B1%2C513%2C900%7D3-710%5E2%3D%5Cdfrac%7B1600%7D3)
You get the standard deviation by taking the square root of the variance, and so
![\sqrt{V[X]}=\sqrt{\dfrac{1600}3}\approx23.09](https://tex.z-dn.net/?f=%5Csqrt%7BV%5BX%5D%7D%3D%5Csqrt%7B%5Cdfrac%7B1600%7D3%7D%5Capprox23.09)
Answer:
A solid figure whose bases or ends have the same size and shape and are parallel to one another, and each of whose sides is a parallelogram.
Step-by-step explanation:
Answer:
D.
Step-by-step explanation:
