Đáp án:
Giải thích các bước giải:
g) `(a+b+c)^2+(a-b-c)^2+(b-c-a)^2+(c-a-b)^2`
`=a^2+b^2+c^2+2ab+bc+2ac+a^2+b^2+c^2-2ab-2ac+2abc+b^2+c^2+a^2-2bc-2ab+2ac+c^2+a^2+b^2-2ac-2bc+2ab`
`=4a^2+4b^2+4c^2+(2ab-2ab-2ab+2ab)+(2bc+2bc-2bc-2bc)+(2ac-2ac+2ac-2ac)`
`=4a^2+4b^2+4c^2`
h) `(a+b+c+d)^2+(a+b-c-d)^2+(a+c-b-d)^2+(a+d-b-c)^2`
`=2[(a+b)^2+(c+d)^2]+2[(a-b)^2+(c-d)^2]`
`=2[(a+b)^2+(a-b)^2+(c+d)^2+(c-d)^2]`
`=2[2(a^2+b^2)+2(c^2+d^2)]`
`=4(a^2+b^2+c^2+d^2)`
