4X+9Y=12 3Y-2X=1 7X+5z=4分之19

9y=3x-(x-1),4(x+y)-(2x+4)=8y 3x-y+x=3 4【X-y-1】=3【1-y】-1 5x-4y+4x=3 2x+y-3x=11 【 x除以2 】-【y 除以3】 =2 2x+7y-3x=19 x+y+x=12 3x+2y-x=18 3(x+y)-2(x-y)=11 4(x+y)+3(x-y)=9 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 (7x-2y)(3x-2y-1)-(4x+3y)(9x+6y)其中x=2y=1 (3x+2y)(4x-5y)-12(x+y)(x-y)+7xy,其中x=2011,y=-1, 方程题4道1.4(x-y-1)=3(1-y)+3.5 (x/2)+(y/3)=2 2.2(x-y)/3-(x+y)/4=13/6 6(x+y)-4(2x-y)=16 3.3x-y+z=3 2x+y-3z=9 x+y+z=12 4.5x-4y+4z=13 2x+7y-3z=19 3x+2y-z=18 x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=? 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 导数的计算练习题导数的计算（1）y=x^5 （2)y=sinx(3)y=1/x^3(4)y=5^√x(5)y=cosx(6)y=5^x(7)y=log3^x(8)y=lnx(9)f(x)=x^3-x^2-x+1(10)y=2x^3-3x^2+4x-1(11)y=x inx（12）y=xsinx-cosx(13)y=cosx/x(14)y=3x(x^2+2)(15)f(x)=(x-1)^2+3(x-1)(16)f(x)=1 用代入消元法解下列方程：（1）y=2x （2）x=y-5/2 x+y=12 4x+3y=65（3）x+y=11 (4) 3x-2y=9x-y=7 x+2y=3我预习二元一次方程,不过不是很懂.(1)y=2x （2）x=y-5/2x+y=12 4x+3y=65 (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 先化简再求值; 解方程组 x(x-y)-y(x+y)+2xy 其中x=2 ,y=-22.x[x-x(x-1)],其中x=-2解方程组4x+3y=12x-y=32.y+1=2x 4x-y=2 3.2x+2y=0 2x-y+24=0 帮忙解一些方程组(1)3x-2y=6 2x+3y=17 (2)5x+6y=15.2 3x-2y=-0.4(3)2(x+y)-3y=7 4(x-9)=3(y-2)(4)3(x+y)-4(x-y)=4 x+y/2+x-y/6=1 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 解方程组{2(x-y)/3 - x+y/4=-1 6(x+y)-41(x-y)=12