The intersection of 8th street and J street can be determined by setting up an equation for each line segment given the points mentioned above. Note that the equation of a line can be obtained from two points such that:
y - y1 = m(x-x1), where m = (y2-y1)/(x2-x1)
For instance, the equation for 8th street is given by: y - 4 = [(9-4)/(6-1)]*(x-1). On the other hand, the equation for J street is given by: y + 14 = [(4+14)/(-5-4)]*(x-4). Simplifying the 2 equations we get: Eqn. (1) y = x + 3 and Eqn. (2) y = -2x - 6
Solving the 2 equations simultaneously, we obtain x = -3, y = 0. Thus, if the city council extends 8th street in a straight line, it will intersect J street at (-3,0).