A table top would be a good representation of a plain because it is a flat surface, and isn't a 3D object, if that makes sense. A box wouldn't be a plane because it has 6 different sides but a table only has one side and one plane. hope this helps :)
Answer:
94m^2
89.1mm^2
Step-by-step explanation:
By definition of covariance,
![\mathrm{Cov}(U,V)=E[(U-E[U])(V-E[V])]=E[UV-E[U]V-UE[V]+E[U]E[V]]=E[UV]-E[U]E[V]](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28U%2CV%29%3DE%5B%28U-E%5BU%5D%29%28V-E%5BV%5D%29%5D%3DE%5BUV-E%5BU%5DV-UE%5BV%5D%2BE%5BU%5DE%5BV%5D%5D%3DE%5BUV%5D-E%5BU%5DE%5BV%5D)
Since
and
, we have
![E[U]=2E[X]+E[Y]-1](https://tex.z-dn.net/?f=E%5BU%5D%3D2E%5BX%5D%2BE%5BY%5D-1)
![E[V]=2E[X]-E[Y]+1](https://tex.z-dn.net/?f=E%5BV%5D%3D2E%5BX%5D-E%5BY%5D%2B1)
![\implies E[U]E[V]=(2E[X]+E[Y]-1)(2E[X]-(E[Y]-1))=4E[X]^2-(E[Y]-1)^2=4E[X]^2-E[Y]^2+2E[Y]-1](https://tex.z-dn.net/?f=%5Cimplies%20E%5BU%5DE%5BV%5D%3D%282E%5BX%5D%2BE%5BY%5D-1%29%282E%5BX%5D-%28E%5BY%5D-1%29%29%3D4E%5BX%5D%5E2-%28E%5BY%5D-1%29%5E2%3D4E%5BX%5D%5E2-E%5BY%5D%5E2%2B2E%5BY%5D-1)
and

![\implies E[UV]=4E[X^2]-E[Y^2]+2E[Y]-1](https://tex.z-dn.net/?f=%5Cimplies%20E%5BUV%5D%3D4E%5BX%5E2%5D-E%5BY%5E2%5D%2B2E%5BY%5D-1)
Putting everything together, we have
![\mathrm{Cov}(U,V)=(4E[X^2]-E[Y^2]+2E[Y]-1)-(4E[X]^2-E[Y]^2+2E[Y]-1)](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28U%2CV%29%3D%284E%5BX%5E2%5D-E%5BY%5E2%5D%2B2E%5BY%5D-1%29-%284E%5BX%5D%5E2-E%5BY%5D%5E2%2B2E%5BY%5D-1%29)
![\mathrm{Cov}(U,V)=4(E[X^2]-E[X]^2)-(E[Y^2]-E[Y]^2)](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28U%2CV%29%3D4%28E%5BX%5E2%5D-E%5BX%5D%5E2%29-%28E%5BY%5E2%5D-E%5BY%5D%5E2%29)
![\mathrm{Cov}(U,V)=4V[X]-V[Y]=4a-a=\boxed{3a}](https://tex.z-dn.net/?f=%5Cmathrm%7BCov%7D%28U%2CV%29%3D4V%5BX%5D-V%5BY%5D%3D4a-a%3D%5Cboxed%7B3a%7D)
Step-by-step explanation:
x-intercept: where y = 0
Set y to zero to find x.
0 = ½x + 3
-3 = ½x
x = -6
(-6, 0)
C - is a hypotenuse,
so we can use Pythagorean theorem.
c² =a² +b²
c² = 8²+12²=64 + 144 = 16*4 +16*9=16(4+9) =16*13
c²=16*13
c=√(16*13)=√16*√13=4√13
c=4√13
Answer C. 4√13