(2) Equation 2x+2 > can be obtained. =2 and 4-2x > =2。 Get 0

2. If the average value of (1) is x+ 1, then the equation x+ 1 < =2x and x+ 1

(2)a=b=c .

Suppose a < = b < = c, then a+b+c=3a and b+c=2a are deduced. A<= b & lt=c, so only a = b = c.

3. Through reasoning, the simultaneous equation can be 2x+y+2 = x+2y = 2x-y, and it is deduced that x=-3, y=- 1.x+y=-4.