问题
解答题
先化简后求值:[(x-y)2+(x+y)(x-y)]÷2x,其中x=3,y=1.5.
答案
[(x-y)2+(x+y)(x-y)]÷2x,
=[(x2-2xy+y2)+(x2-y2)÷2x,
=(2x2-2xy)÷2x,
=x-y,
当x=3,y=1.5时,原式=3-1.5=1.5.
先化简后求值:[(x-y)2+(x+y)(x-y)]÷2x,其中x=3,y=1.5.
[(x-y)2+(x+y)(x-y)]÷2x,
=[(x2-2xy+y2)+(x2-y2)÷2x,
=(2x2-2xy)÷2x,
=x-y,
当x=3,y=1.5时,原式=3-1.5=1.5.