K+b=-2 -3k+b=-9，k=7/4 b=- 15/4。

∴ straight line y=7/4x- 15/4

(2) let y = 7/4x+m. Then when 7/2+m=7, m=7/2∴y=7/4x+7/2.

(3) Let y=7/4x- 15/4=0 to get x= 15/7. ( 15/7,0); When x=0, y=- 15/4 (0,-15/4).

The enclosed area is1/2 *15/7 *15/4 = 225/56.

(4) the upper part of the x axis, ∴ x >; 15/7

(5) When x=-2 and y = 7/4 *(2)- 15/4 =-29/4; ; When x=4, y = 7/4 * 4-15/4 =13/4.

∴-29/4<； = y & lt= 13/4

2. solution: m-1= 0 ∴ m =1of (1)

(2) 1-2m

(3)M- 1 >； 0∴m>； 1