原式=2(a²+b²)(a+b)²-(a+b)²(a-b)²
=(a+b)²[2(a²+b²)-(a-b)²]
=(a+b)²(2a²+2b²-a²+2ab-b²)
=(a+b)²(a²+b²+2ab)
=(a+b)^4
2(a² + b²)(a + b)² - (a² - b²)²
= 2(a² + b²)(a + b)² - (a + b)²(a - b)²
= (a + b)²[2(a² + b²) - (a - b)²]
= (a + b)²(a² + b² + 2ab)
= (a + b)²(a + b)²
= (a + b)^4
答:
原式
=2(a^2+b^2)(a+b)^2-(a+b)^2(a-b)^2
=(a+b)^2(2a^2+2b^2-a^2-b^2+2ab)
=(a+b)^2(a^2+b^2+2ab)
=(a+b)^2(a+b)^2
=(a+b)^4