2x+9y=81 3x+y=34 2.9x+4y=35 8x+3y=30 3.7x+2y=52 7x+4y=62 4.4x+6y=54 9x+2y=87 5.2x+y=7 2x+5y=19 6.x+2y=21 3x+5y=56 7.5x+7y=52 5x+2y=22 8.5x+5y=65 7x+7y=.

66x+17y=396725x+y=1200答案:x=48y=47(2)18x+23y=230374x-y=1998答案:x=27. x=97y=59(100)51x-97y=29719x-y=1520答案:x=80y=39方程组

5x+3y=8,3x+5y=8 6x-7y=5,x+2y=4 10x-8y=14,x+y=5 4x+7y=3,x+y=0 3x+y=10,7x-y=20 44x+10y=27,x+y=1 8x-y=0,x+y=18 11x-y=12,11y-x=-12 5x+6y=27,2x+3y=12 7x-2y=4,x+2y=12 (2x+y)-5y=2,2x-5y=0 7x-3y=3,3x+2y=21 7x+2y=21,y-6x=1 10x-8y=0,3x-2y=2 3x+y=10,5x-7y=8

66x+17y=3967 25x+y=1200 答案:e68a84e8a2ad7a6431333332396163x=48 y=47 (2) 18x+23y=2303 74x-y=1998 答案:x=27 y=79 (3) 44x+90y=7796 44x+y=3476 答案:.

＂2x+9y=81 3x+y=34 9x+4y=35 8x+3y=30 7x+2y=52 7x+4y=62 4x+6y=54 9x+2y=87 . 5x+5y=45 7x+9y=69 答案1)为前一个方程,2)为后一个方程.下同2x+9y=81 3x+y=.

例:解二元一次方程: x + y =10 2x + 3y =18 解:令“x + y=10”为1式,“2x + 3y =18”为2式: 1式*2-2式,得:-y = 2,即y = -2 将y = -2代入1式,得x = 12 x、y的值分别是 x = 12 y = -2

展开全部1) 66x+17y=3967 25x+y=1200 答案:x=48 y=47 (2) 18x+23y=2303 74x-y=1998 答案:x=27 y=79 (3) 44x+90y=7796 44x+y=3476 答案:x=79 y=48 (4) 76x-66y=.

3x+5x=48 x=614x-8x=12 x=2 6*5+2x=44 x=720x-50=50 x=5 28+6x=88 x=1032-22x=10 x=1 4y+2=6 y=1 x+32=76 x=443x+6=18 x=416+8x=40 x=32x-8=8 x=84x-3*9=29 x=98x-.

题目有没啊…如果没有特殊条件的话需要一个方程组…至少要2个方程来解2个未知数…x+y=45 (1)x-y=12 (2)(2)减(1)得 (x+y)+(x-y)=572x=57 x=28.5 所以28.5+y=45 y=45-28.5=16.5答:x=28.5 y=16.5

(1) x+y=4① x-y=2② ①+②,得:2x=6 x=3 x=3代入①:3+y=4 y=1(2) x+2y=32 ① x-y=8 ② 由①得,x=32-2y ③ 把③代入②,得: 32-2y-y=832-3y=83y=24 y=8 y=8代入③ :x=32.