Chapter 1 - 1.1 - Graphs of Equations - 1.1 Exercises - Page 79: 73

See graph

For $t=0$: $$y=1,200,000-80,000(0)=1,200,000$$ For $t=10$: $$y=1,200,000-80,000(10)=400,000$$ Thus, two points on the graph are $(0,1200000)$ and $(10,400000)$. Using the two points, the sketch of the graph of the equation is as shown.