问题
解答题
(1)先化简,再求值:[(x+y)2-y(2x+y)-8x]÷8x,其中x=-3. (2)计算:|
|
答案
(1)[(x+y)2-y(2x+y)-8x]÷8x,
=(x2+2xy+y2-2xy-y2-8x)÷8x,
=(x2-8x)÷8x,
=
x-1,1 8
当x=-3时,原式=
×(-3)-1=-1 8
;11 8
(2)原式=
-1+1-3
=0.3
(1)先化简,再求值:[(x+y)2-y(2x+y)-8x]÷8x,其中x=-3. (2)计算:|
|
(1)[(x+y)2-y(2x+y)-8x]÷8x,
=(x2+2xy+y2-2xy-y2-8x)÷8x,
=(x2-8x)÷8x,
=
x-1,1 8
当x=-3时,原式=
×(-3)-1=-1 8
;11 8
(2)原式=
-1+1-3
=0.3