The first thing I would do is realize that if I put 0 in for x, I get 25 for y or the point (0, 25). This tells me that i need to increase my x value to bring the y down onto the graph. So lets pick 8 for x.
Plug and chug for y
y = -3 (8) + 25 = -24 + 25 = 1
now I have a point (8,1)
since 8 worked for the graph, lets pick another number close to 8 like 6
Plug and chug for y
y = -3 (6) + 25 = -18 + 25 = 7
now. we have a second point (6, 7)
with 2 points we can graph the line, or you can add points if you need to.
