Is the solution x 1= 1? x2=-3

When x=0, y=3.

So the coordinates of point A are (-3,0), point B is (1 0), and point C is (0,3);

(2) Let the analytical formula of straight line AC be y=kx+b, because it passes through point A and point C. 。

So what? 3k+b=0b=3，

The solution is k = 1b = 3.

Therefore, the analytical formula of straight line AC is y = x+3;

(3) The coordinate of point m is (m, n). According to the meaning, AB = 3+ 1 = 4.

∫S△MAB= 12ab×n, while S△MAB = 6.

∴n=3.

At this time m is (m, 3),

Point m is on a parabola,

∴-m2-2m+3=3，

The solution is m 1=-2, m2=0.

So the coordinate of point M is (-2,3).