(1)4X+7Y=144 (2)12X-8Y=24求X和Y

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 (1)4X+7Y=144 (2)12X-8Y=24求X和Y (3x+2y)(4x-5y)-12(x+y)(x-y)+7xy,其中x=2011,y=-1, 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 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 1 已知x+y/y=7/3 求x+y/x-y等于什么2 若x+4/3=y+3/2=z+8/4 且x+y+z=12 求x、y、z的值 请解答方程组：（39）2x+y=5 (40)x+y=7 (41)2x+3y=12 (42)2x+y=3ax+3y=7 2x-y=8 3x+4y=17 3x-5y=11(43)3x+y=82 (44)3(x-1)=y+5 45 x/4+y/3=7 (46)x+y/3 +x-y/2=610x-11y=87 5(y-1)=3(x+5) 2/3x+y/2=14 3(x+y-)2(x-y)=28 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 x+2y=2x+y+1=7x-y 求：2x-y? {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/（x+2y-12Y²/x-2y)的值 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 4(x+2)=1-5y 4(x+y)-3(x-y)=12 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 已知X和Y满足3X+4Y=2,X-Y-1/7 2x—3y+5=0 3x+2y=12 y=2x 7x—3y=4 Y+1=三分之x+1 2x—3y=1 方程组