total monthly revenue

[salma]

The total monthly revenue, in thousands of dollars, earned by the Rose Trucking Company is given by
R (m)= -5/2m^2 +60m,
m2 + 60m,
where m represents months after January 1, 2005. Use this function to determine R(8).
A $640,000
B $880,000
C -$100,000
D $320,000

How would I do this??

 

[girodd]

I don't understand the second line, but R(8) means to replace m by 8 and work out the result.

 

[salma]

my bad, that "m2+60m" was an accident. ignore it. ok so I plugged in 8. i have R(m) = (-5/2)8^2 + 60(8)

so -160+60(8)
which is 320.
so its D
Thank you!