3x+y=9
2x+y=8
the graphing method

No thats standard form. to graph it you need to turn it into slope-intercept form which is y=mx+b where m is the slope (rise over run) and b is the y intercept.

for example to get it for 3x+y=9 you would take away the 3x and put it on the other side.
 3x+y=9
-3x    -3x and that would become:

y= - 3x+9

thats graphing method.

3x + y = 9 ⇒ 6x + 2y = 18
2x + y = 8 ⇒ 6x + 3y = 24
                            -1y = -6
                             -1     -1
                               y = 6
                       3x + 6 = 9
                             -6   -6
                             3x = 3
                              3     3
                               x = 1
                         (x, y) = (1, 6)

In all honesty, there really is no “work” per say to show. mainly it’s just using the process of elimination. the question is asking which domain(s) would be the most appropriate for the function c(n). n is the number of observed vehicles so right away, 1, 2, and 3 can be eliminated.why? 1, 2 start in the negatives and therefore it is impossible to observe negative cars. so, #4 would be the best answer to the given problem.