{2x+3y=1,4x-y=5 {x-2y=1,3x=2y {4x-3y=15,3x+2y=7 {3y-4x=6,3x-4y+1=0 {x=5-3y,3x-6y=6 {m-3n=-5,5m+2n=26 求计算过程及答案
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{2x+3y=1,4x-y=5 {x-2y=1,3x=2y {4x-3y=15,3x+2y=7 {3y-4x=6,3x-4y+1=0 {x=5-3y,3x-6y=6 {m-3n=-5,5m+2n=26 求计算过程及答案
{2x+3y=1,4x-y=5 {x-2y=1,3x=2y {4x-3y=15,3x+2y=7 {3y-4x=6,3x-4y+1=0 {x=5-3y,3x-6y=6 {m-3n=-5,5m+2n=26 求计算过程及答案
{2x+3y=1,4x-y=5 {x-2y=1,3x=2y {4x-3y=15,3x+2y=7 {3y-4x=6,3x-4y+1=0 {x=5-3y,3x-6y=6 {m-3n=-5,5m+2n=26 求计算过程及答案
1、代入法
从方程1得到 x=(-3y-1)/2
代入方程2,得到-6y-2-y=5
解得 y=-1 x= 1
2、消元法
方程1乘以2 - 方程1,得到 6y-(-y)=-2-5
所以y=-1
将y=-1代入任一方程,得到 x=1
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)
先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5
(x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
{(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=?
x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=?
{x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
3x-2y=1 4x-5y
(x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2
化简求值{(x=2y)(5x-2y)-(3x+2y)(3x-2y)]/4x,其中x=2,y=-1
先化简 再求值 (2x-y)(y+x)-(x-2y)(2y+x)-(-3y+x)^2其(√x+1)+y^2+4=-4y
已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙