{2x+3y=14 {4x-5y=6用代入法怎么求,

6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5 已知y=2x,z=3[y+x],试用含有x的代数值表示x+y+z 4(x+y)-3(x-y)=14,x+y/2 + x-y/3=6 用简便方法能解吗? x+y/2+x-y/3=6,4(x+y)-5(x-y)=2用加减消元法解方程组 （2x-y+4）^2+|x+y|=o,则代数值4x+7y=—— 化简在求值 x²+x³-6y²+1-5x³-x+(y-x²)+6(x²+y²+y) x=3 y=2分之1化简在求值 x²+x³-6y²+1-5x³-x+(y-x²)+6(x²+y²+y) x=3 y=2分之1 先合并同类项在代值 用代入法解下列方程组 1）.x=3y,x+4y=14 2).x-3=2y,2x+1=3y 3).3x-5y=6,x+4y=-154).2x-y=5,3x+4y=2 5).3x+1=4y-x=y+2 把方程3x+2y=3写成用含x的代式表示y的形式;________________. 1:4(x-100)+3y=5 2:6(x-y)-2(x+y )=14 x-100=-y 3(x-y)+(x+y)=5 先无视上面的1.4(x-100)+3y=5x-100=-y2.6(x-y)-2(x+y )=143(x-y)+(x+y)=5 x+y/2+x-y/6=5 2(x+y)-3(x-y)=-2 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11