Expert: Scott A Wilson - 7/2/2010

Question
Hey I'm unclear about a few problems I have, I hope you can help:

1. Translate into an algebraic expression.  The total cost of producing x units for which the fixed cost are $3200 and the cost per unit is $80

I came up with $80/x = $3200

2.I'm viewing a graph in my book, but I still can't tell if the symmetry at the origin, x-axis, or y-axis?
The problem is:

y^2= 4-x ; I'm thinking x-axis
y= absolute value of x +2 ; I'm thinking x-axis also

Please help! Thanks you
y

Answer
1. Given the cost is C and the units are x, the equation would be C = $3200 + $80x.

2. At x = 4, y is 0; at x = 0, y = ±2; at x = t, y = ±√(4-t);
from this, it can be seen that the function is reflective around the x axis
since the value of y at any x is the same above and below the axis.