I think is
y = x - 1y = 3x - 9
y - y = x - 3x = -9
0 = - 2x = - 9
The y-intercept is 2. The y-intercept occurs when x is 0. In the graph, y is 2 when x is 0.
Well 6,000 is actually equal to 1,000 x 6.
It turns out that 1,000 = 10 x 10 x 10 = 10^3
So the answer to your question is:
6 x 10^3