17x+12y<20400; 12y<20400-17x; y<1700-17x/12.
The whole area to the left of the red line is the inequality 17x+12y<20400. Note that the base of the triangle formed by the axes and the line has length 1200 while the vertical leg is length 1700. Hence the slope of the line is 17/12. The means the y-intercept is 1700 and the x-intercept is 1200.