作业帮解方程 3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y=3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y= 28000.96X+0.64Y=2800*0.92
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/02 12:45:28
解方程 3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y=3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y= 28000.96X+0.64Y=2800*0.92
解方程 3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y=
3(2X-Y)+4(X-2Y)=87
2(3X-Y)-3(X-Y)=82
1-0.3(Y-2)=(X+1)/5
(Y-3)/4=(4X+9)/20-15
X+Y= 2800
0.96X+0.64Y=2800*0.92
解方程 3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y=3(2X-Y)+4(X-2Y)=87 2(3X-Y)-3(X-Y)=82 1-0.3(Y-2)=(X+1)/5 (Y-3)/4=(4X+9)/20-15 X+Y= 28000.96X+0.64Y=2800*0.92
(1)原式：3(2X-Y)+4(X-2Y)=87
2(3X-Y)-3(X-Y)=82
=> 10x-11y=87
3x+y=82 (=> y=82-3x代入10x-11y=87)
=> 解为：x=23,y=13
(2)原式：1-0.3(Y-2)=(X+1)/5
(Y-3)/4=(4X+9)/20-15
=> 2x+3y=14
4x-5y=-276
=> 4x+6y=28
4x-5y=-276
=> 解为：x=-379/11,y=304/11
(3)原式：X+Y= 2800
0.96X+0.64Y=2800*0.92
=》 X+Y= 2800
3x+2y=8050
=> 2X+2Y= 5600
3x+2y=8050
=>解为：x=2450,y=350
完成
3(2X-Y)+4(X-2Y)=87 <==> 10x-11y=87 (1)
2(3X-Y)-3(X-Y)=82 <==> 3x+y=82 (2)
由(1)+11*(2)得，43x=87+902 ==> x=989/43=23 (3)
将（3）代入（2）中，得 y=82-3*23=13
1-0.3(Y-2)=(X+1)/5 ...
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3(2X-Y)+4(X-2Y)=87 <==> 10x-11y=87 (1)
2(3X-Y)-3(X-Y)=82 <==> 3x+y=82 (2)
由(1)+11*(2)得，43x=87+902 ==> x=989/43=23 (3)
将（3）代入（2）中，得 y=82-3*23=13
1-0.3(Y-2)=(X+1)/5 等式两边都乘以10得，10-3y+6=2x+2 即 2x+3y=14 (1)
(Y-3)/4=(4X+9)/20-15 等式两边都乘以20得，5y-15=4x+9-300 即 4x-5y=276 (2)
由2*（1）-（2）得，11y=-248 ==> y=-248/11,代入（1）中得，x=449/11
0.96X+0.64Y=2800*0.92 ==> 0.32x+0.64(x+y)=2800*0.92 又 X+Y= 2800 ==>
0.32x+0.64*2800=2800*0.92 ==> 0.32x=(0.92-0.64)*2800 ===> x=2450
y=2800-x=2800-2450=350
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