已知m+n=10,mn=24,求值:(1)m^2+n^2;(2)(m-n)^2
问题描述:
已知m+n=10,mn=24,求值:(1)m^2+n^2;(2)(m-n)^2
答
m^2+n^2
=(m+n)^2-2mn
=10^2-2x24
=100-48
=52
(m-n)^2
=(m+n)^2-4mn
=10^2-4x24
=100-96
=4