(2x+y+1)²≤(x+2y+2)²
(2x+y+1)²-(x+2y+2)²≤0
平方差公式:
[(2x+y+1)+(x+2y+2)][(2x+y+1)-(x+2y+2)]≤0
(3x+3y+3)(x-y-1)≤0
即得到
(x+y+1)(x-y-1)≤0
(2x+y+1)²≤(x+2y+2)²
(2x+y+1)²-(x+2y+2)²≤0
平方差公式:
[(2x+y+1)+(x+2y+2)][(2x+y+1)-(x+2y+2)]≤0
(3x+3y+3)(x-y-1)≤0
即得到
(x+y+1)(x-y-1)≤0