1：m^2+n^2
=(m+n)^2-2mn
=100-48
=52
2：(m-n)^2
=m^2+n^2-2mn
=52-48
=4这个一定对吗对的再问你一个；(a加b减三)乘以(a减b加三)等于几(a+b-3)(a-b+3)=[a+(b-3)][a-(b-3)]=a^2-(b-3)^2=a^2-(b^2+9-6b)=a^2-b^2+6b-9x的2次方减2x加y的2次方加6y加10对于0,求x,y的值x^2-2x+y^2+6y+10=0(x-1)^2+(y+3)^2=0x=1,y=-3