3(x-y)+5(x-y)=19 4(x+y)-2(x-y)=-1解方程组是3（x+y)_数学解答

3(x-y)+5(x-y)=19 4(x+y)-2(x-y)=-1
解方程组
是3（x+y)

人气：433 ℃　时间：2020-05-29 05:55:53

解答

题目有误,请改正
3(x+y)+5(x-y)=19 ,①
4(x+y)-2(x-y)=-1.②
①*2+②*5,26(x+y)=33,
x+y=33/26,③
①*4-②*3,26(x-y)=79,
x-y=79/26,④
[③+④]/2,x=28/13,
[③-④]/2,y=-23/26.
本题有多种解法.