Get m=3.

2.y decreases with the increase of x, so 2m+ 1

3. The image passes through one, two or three quadrants.

So 2m+1>; 0 m -3 >0 get m> three

4 when k >; O y=kx+b, and y=x+2 when the point (0. -1) (0,2) is replaced.

When k < O y=kx+b and y=-x+2, the point (01) (0,2) is substituted.