Substitute (-1, -3) to get machine 2x+y+5=0 with t=5.

The abscissa of the midpoint coordinate of 13 AB is the average of the abscissa of A and B, and the ordinate is the same, so the midpoint coordinate is (1, 3).

X/4-y/2= 1 means x-2y=4. Replace x-2y=t with (1, 3) to get t=-5, which means x-2y+5=0.

14

The solution of simultaneous equations is x=(3m-4)/(mm+3) y=(4m+6)/(mm+3) (in every step of solving equations, we should pay attention to the negative content. The most common thing is that the denominator cannot be 0. If the denominator is always greater than 0, there is no need to discuss other issues. )

The second quadrant represents x "0y" 0, and you can get -3/2.

Taken together, the range of M (-3/2, 4/3)