4(x+2)=1-5x 3(y+2)=3-2 y/2+x/3=13 y/3-x/4=3 x+y=420 30%x+40%y=160*180% 2x-1/5+3y-2/4=2 3x+1/3-3y+2/

题目

4(x+2)=1-5x 3(y+2)=3-2 y/2+x/3=13 y/3-x/4=3 x+y=420 30%x+40%y=160*180% 2x-1/5+3y-2/4=2 3x+1/3-3y+2/
4(x+2)=1-5x
3(y+2)=3-2
y/2+x/3=13
y/3-x/4=3
x+y=420
30%x+40%y=160*180%
2x-1/5+3y-2/4=2
3x+1/3-3y+2/4=4/3
x/2+y/3=2
2x+3y=28

答案

4x+8=1-5x(4+5)x=1-8x=-7/93y=1-6y=-5/3;y/2=13-x/3y=26-2x/3(26-2x/3)/3-x/4=3-(2/9+1/4)x=3-26/3x=12y=26-24/3=18;y=420-x0.3x+0.4(420-x)=160*1.8-0.1x=120x=-1200y=1620;化简可得2x+3y=2.7 x-y=1/6x=y+1/6 2(y+1...