The Sean's number is x. Formulate the equation:
x * 5 : 2 = 30
5x = 30 * 2
5x = 60
x = 60 : 5
x = 12
Answer: the Sean's number is 12.
To put it in the simplest words :
Get rid of the parentheses and add like so:

<span>Combine like terms
2n^3+n^3= 3n^3
-8n^2 remains the same since there are no like terms for it
8n also remains the same
-9+7=-2
Put all of the numbers together
3n^3-8n^2+8n-2
Final answer:B - the 2nd one</span>
The diameter of the wheel is 30 inches, therefore the radius is 15 inches.
We calculate the angular velocity (w) of this using the formula:
w = v / r
w = 60 mph / 15 inches = 4 mph / inches
Since the flange is 1 inch beyond the rim, hence the effective radius for this is 16 inches.So the velocity on the outer edge is:
v = w r
v = (4 mph / inches) * 16 inchesv = 64 mph
(x,y)=(6,-4)
1: 3x-y=22
2: 3x+2y=10