2x-5y=-21 4x+3y+23 用加减消元法解

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 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 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 x+y/2+x-y/3=6,4(x+y)-5(x-y)=2用加减消元法解方程组 1.{3x+2y=73x-4y+12 {x-6y=-23x+4y=53 {8x+3y+2=06x+5y+7=04 {2x-y=650%x+12.5%y=25%×35 {|x |+y=2|x |+2y=3希望可以有过程,用加减消元法谢谢了 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 用加减法解方程{2x-5y=-21 4x+3y=23 2x-5y=-21 4x+3y+23 用加减消元法解 用加减消元法解下列方程组：(1)4x-3y=14,5x+3y=31(2)2x-5y=-21,4x+3y=23(3)4x+7y=-19,4x-5y=17(4)3(x-1)=y+5,5(y-1)=3(x+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) 二元一次方程组.1.{5x-2y-4=0 x+y-5=0 2.{3x+y=7 5x-y+9 3.{2x-5y=-21 4x+3y=23 3y=x+5 2x+5y=23 2x+3y=7 3x-5y=1 3x+5y=5 3x-4y=23 用二元一次方程解 因式分解(x-2y)(x-3y)+(x-4y)(x-5y)+（x-3y)(x-5y)+(x-2y)(x-4y) (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 先化简,后求值（x+5y)(x+4y)(x-y)(x+y),其中,x=-2又2/3,y=3/7,用公式计算