Question

已知x=a+b,y=a-b,用简便的方法计算代数式（x*2+Y*2）*2—（x*2—y*2）*2 已知x=a+b,y=a

Answer 1

(x²+y²)²-(x²-y²)²=(x²+y²+x²-y²)(x²+y²-x²+y²)=4x²y²=4(a+b)²(a-b)²=4(a²-b²)²=4a^4-8a²b²...