SOS 谁能帮我解数学题,谢谢了!!!

来源:百度知道 编辑:UC知道 时间:2024/06/08 17:11:24
已知(x-3)的平方加上3y+1的绝对值等于0.求3xX的平方y-[2xyY的平方-2(xy-3\2)+xy)+3xyY的平方的值.

(x-3)^2+|3y+1|=0
(x-3)^2=0, x=3
|3y+1|=0. y=-1/3

3x^2y-[2xy^2-2(xy-3/2)+xy]+3xy^2
=3x^2y-[2xy^2-2xy+3/2+xy]+3xy^2
=3x^2y-[2xy^2-xy+3/2]+3xy^2
=3x^2y-2xy^2+xy-3/2+3xy^2
=x^2y+xy+3xy^2-3/2
=xy(x+1+3y)-3/2
=-3*1/3(3+1-3*1/3)-3/2
=-3-3/2
=-9/2

先解出X、 Y 因为(X-3)的方大于等于0 3Y+1的绝对值大于等于0 ,而和为0 ,
则只能同时为0 X-3=0 3Y+1=0联立即可 ,再求后面的

二分之九噻!具体请见首席运营官的慷慨陈词了啦!抱歉,小ZX!

用:x-3)^2+|3y+1|=0
(x-3)^2=0, x=3
|3y+1|=0. y=-1/3

3x^2y-[2xy^2-2(xy-3/2)+xy]+3xy^2
=3x^2y-[2xy^2-2xy+3/2+xy]+3xy^2
=3x^2y-[2xy^2-xy+3/2]+3xy^2
=3x^2y-2xy^2+xy-3/2+3xy^2
=x^2y+xy+3xy^2-3/2
=xy(x+1+3y)-3/2
=-3*1/3(3+1-3*1/3)-3/2
=-3-3/2
=-9/2
简简单单便做出来了啊!是:9/2=4.5