a=1/20x+20,b=1/20x+19,c=1/20x+21,求a方加b方家c方减去ab,减去bc,减去ac等于?

问题描述:

a=1/20x+20,b=1/20x+19,c=1/20x+21,求a方加b方家c方减去ab,减去bc,减去ac等于?

a-b=1,b-c=-2,c-a=1a²+b²+c²-ab-bc-ac=(2a²+2b²+2c²-2ab-2bc-2ac)/2=[(a²-2ab+b²)+(b²-2bc+c²)+(c²-2ac+a²)]/2=[(a-b)²+(b-c)²+(c-a)²...