M的2次方=N+2,N的2次方=M=2.M不等于N.求M的3次方-2MN+N的3次方_数学解答

M的2次方=N+2,N的2次方=M=2.M不等于N.求M的3次方-2MN+N的3次方

人气：220 ℃　时间：2020-06-27 13:57:01

解答

m²=n+2n²=m+2相减m²-n²=n-m(m+n)(m-n)=-(m-n)m≠nm-n≠0把m-n约分m+n=-1m²=n+2n²=m+2相加m²+n²=m+n+4=-1+4=3由m+n=-1平方m²+n²+2mn=1所以mn=-1m³-2mn+n&sup...