In words, multiply x by 14 and subtract the result from 1700 to get y.
There is a y value for every x value.
Linear means line, so when the graph is plotted it’s a straight line. The line is found by working out the intercepts: y=1700 and x=1700/14=850/7 (about 121.4) and drawing a line through 1700 on the y axis and 121.4 on the x axis.