怎么做,(ab+c)(ab-c)=?
(-x²-y)( )=y²-x²
( +m)²=4n²+ +
若(x-2)²+(y+3)²=0,则x+y=
怎么做,(ab+c)(ab-c)=?
(-x²-y)( )=y²-x²
( +m)²=4n²+ +
若(x-2)²+(y+3)²=0,则x+y=
329²-71²=(329-71)(329+71)=258*400=103200
(ab+c)(ab-c)=a^2b^2-c^2
(-x-y)(x-y)=y²-x²
x=2 y=-3 x+y=-1