用加减消元法解下列方程：写得好加100分~①｛x/4+y/3=5,x/3+y/2=7.②｛x:2y=4:3,(2x-1):(4y+1)=3:4.③{6(x+y)=4(x-y)+16,2/3(x-y)=(x+y)/4-1

Question

用加减消元法解下列方程：写得好加100分~
①｛x/4+y/3=5,x/3+y/2=7.②｛x:2y=4:3,(2x-1):(4y+1)=3:4.③{6(x+y)=4(x-y)+16,2/3(x-y)=(x+y)/4-1

Answer 1

1）1式×4/3-2式：4y/9-y/2=20/3-7
y=6 x=12
2）化简：3x-8y=0;8x-12y-7=0
1式×8/3-2式：-64y/3+12y=-7
y=3/4 x=2
3）化简：2x+10y=16;5x-11y=-12
1式×5/2-2式：25y+11y=40+12
y=13/9 x=7/9