Question

Chứng minh rằng:(a+b)(a^2_ab+b²)+(a-b)(a²+ab+b²)=2a³

Answer 1

ap dung hang dang thuc

(a^3+b^3)+(a^3-b^3)=a^3+b^3+a^3-b^3=2a^3 (dpcm)