Solutions (1) and (2), p=2, q=-4.
Method 2: -2, 1 is the equation 2x? +px+q=0,so -2+ 1=-p/2,-2* 1=q/2,
So, p=2 and q=-4.
2、A={x|x? -(a+ 1)x+a & lt; 0} B={x|x? -4x+3≤0}={x| 1≤x≤3} .x? -(a+ 1)x+a=0,x 1= 1,x2 = a。
If a< 1, then a = {x | a
If a> 1, then a = {x | 1
So the range of a is: 1≤a≤3.