S=cost of system
G=cost of games = 3S
total=S+G=652 =>
S+3S=652
4S=652
S=652/4=163
G=3S=3*163=389
The practical domain would be all integers 10 to 50.<span />
8a+2b * -2a + 5b (since there's an invisible -1, at least the 1 is) so the product of that is -16a^2 + 10b^2
You find the circumference and multiply it by the central angle. If the central angle is in degrees, you divide that by 360. If the central angle is in radians, you divide by 2pi.
Simple (Cross multiplication )
7 x
_ _ = 700/8 = 87.5 (100-87.5 = 12.5 is the missing value.
8 100