4(x+2)=1-5x 3(y+2)=3-2 二元一次方程要过程,4(x+2)=1-5x3(y+2)=3-2y/2+x/3=13y/3-x/4=3x+y=42030%x+40%y=160*180%2x-1/5+3y-2/4=23x+1/3-3y+2/4=4/3x/2+y/3=22x+3y=28
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4(x+2)=1-5x 3(y+2)=3-2 二元一次方程要过程,
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
4(x+2)=1-5x 即 4x+8=1-5x 即 9x=-7 即 x = -7/9
3(y+2)=3-2 即 y+2 = 1/3 即 y = -4/3
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y/2+x/3=13
y/3-x/4=3
即 3y + 2x = 78 即 9y + 6x = 234
4y - 3x = 36 即 8y - 6x = 72
所以 17y = 306 所以 y = 18 , x= (78- 3*18 )/2 = 12
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其它的类似道理,二元一次方程最简单的解法就是消元,消元就是把x或者y的系数整成
相等的,然后两式相减;或者整成相反的,然手两式相加
【中学数学解答团】
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
若2x-3y+4=0则x(x*x-1)+x(5-x*x)-6y+7
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=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
{(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) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)=
3x-2y=1 4x-5y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
化简求值{(x=2y)(5x-2y)-(3x+2y)(3x-2y)]/4x,其中x=2,y=-1
(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
初二上学期方程题 4x+y=5 5x+4y=63x-2y=1 2x+3y=13x-2y=7 7x+5y=32x+3y=17 2x-y=-4x+5y=6 2x+y=23x-6y=4 3x+2y=52x+y=73x-4y=53x+y=1x-2y=-1x+y=42x+3y=92x-3y=74x+5y=3x+y=20004x+6y=90003x+5y=113x-2y=42x+3y=215x-2y=5x+y=54x+3y=182x+3y=16x+4y=132x+3y=40x
解下列方程组:{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