S=d/t so in this case it's 75/12 which is 6.25. Round it and you got 6 miles per hour.
4(x+5)+6=2(2x+3)
4x+20+6=4x+6
4x+26=4x+6
Get letters on left...so subtract 4x from right and do same to left
26=6
no solution because 26 does not equal 6
Exact Surface Area = 378pi
Approximate Surface Area = 1186.92
The approximate surface area uses pi = 3.14
The units are cm^2 or "square cm".
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Work Shown:
SA = surface area of cylinder
SA = 2*pi*r^2 + 2*pi*r*h
SA = 2*pi*7^2 + 2*pi*7*20
SA = 2*pi*49 + 2*pi*140
SA = 2*49*pi + 2*140*pi
SA = 98pi + 280pi
SA = 378pi ..... exact surface area
SA = 378*3.14
SA = 1186.92 ..... approximate surface area
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Side note: The diameter 14 cuts in half to get the radius r = 7
You're trying to find constants
such that
. Equivalently, you're looking for the least-square solution to the following matrix equation.
To solve
, multiply both sides by the transpose of
, which introduces an invertible square matrix on the LHS.
Computing this, you'd find that
which means the first choice is correct.
