Question

解方程 a平方+b平方+c平方=ab+bc+ac

Answer 1

a^2+b^2+c^2=ab+bc+ac

a^2+b^2+c^2-ab-bc-ac =0

2a^2+2b^2+2c^2-2ab-2bc-2ac =0

a^2-2ab+b^2+b^2-2bc+c^2+a^2-2ac+c^2 =0

(a-b)^2+(b-c)^2+(a-c)^2=0

(a-b)^2=0,(b-c)^2=0,(a-c)^2=0

a=b,b=c,a=c

a=b=c