Business and Finance word problems (profit expression)

[zhyia]

The revenue for selling y units is R=3y^2-2y+5 and the cost of producting y units is C=y^2+y-3. Find the polynomial that represents profit. Should I subtract to get my answer?

3y^2-2y+5
-y^2+y-3

=2y^4+1y^2+2

 

[tkhunny]

Revenue less Cost is Profit. Good.

3y^2 - y^2 = 2y^2 -- Good.
-2y - y = -3y -- Whoops.
5 - (-3) = 8 -- Whoops.

Take better care in your subtraction. Some folks "change the signs and add".

 

[zhyia]

okay...so you lost me a little
the final answer should be 2y^2-3y+8
so I just got my signs mixed up?

 

[tkhunny]

so I just got my signs mixed up?

That wouldn't be my view. I'm guessing you just forgot how to subtract.