Loreen runs a calligraphy business. Her weekly cost is modeled by the linear equation $C = 1.8n + 35$, where $C$ is the weekly cost in dollars and $n$ is the number of wedding invitations she writes.

ⓐ Find $C$ when $n = 0$: $C = 1.8(0) + 35 = 0 + 35 = 35$ Loreen's weekly cost is $35 when she writes $0$ invitations.

ⓑ Find $C$ when $n = 75$: $C = 1.8(75) + 35 = 135 + 35 = 170$ Her weekly cost is $170 when she writes $75$ invitations.

ⓒ Interpret the slope and $C$-intercept:

• The slope $1.8$ means that the weekly cost increases by $1.80 for every additional invitation written.
• The $C$-intercept is $(0, 35)$, meaning her weekly cost is $35 even if $0$ invitations are written.

ⓓ Graph the equation: To graph this equation, prepare a coordinate plane with a sufficiently large scale to fit the application's data. Start at the $C$-intercept $(0, 35)$. By utilizing the slope $1.8$ as an equivalent ratio (such as moving up $18$ units and right $10$ units, or multiplying to create larger integer steps), plot a second point. Draw a straight line passing through these points to visually represent the business cost model.