## Calculus with Applications (10th Edition)

$C(x)=30x+60$
In a linear cost function, of the form $C(x)=mx+b$, the $m$ represents the marginal cost and $b$ represents the fixed cost (zero units produced). The graph of C(x) passes through the points $(8, 300)$ and $(0,60).$ Slope: $m=\displaystyle \frac{60-300}{0-8}=30$ Slope-intercept equation: (b= the y-intercept) $y=30x+60$ or $C(x)=30x+60$