4/x + 9/y =16/x + 6/y =1x =10,y =15

5X+16X= Y+9Y= X+7X-4X= {5(x-3y)-6=2x+1 3(x+6y)+4=9y+19 ｛3分之2（x-y）=4分之x+y-1 6）x+y)=4(2x-y)+16 解下列方程组{4x-3y=5 2x+5y=9 {x+y=2 x-y=0 {x+2y=6 x-2y=-2 {5x-y=16 3x+2y=20 {2x+3y=-7 3x+2y=7 解方程组 10（x-y)=3(x+y)+15 6(x+y)=4(2x-y)+1610（x-y)=3(x+y)+156(x+y)=4(2x-y)+16 解方程组 10（x-y)=3(x+y)+15 6(x+y)=4(2x-y)+1610（x-y)=3(x+y)+156(x+y)=4(2x-y)+16分开的。 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 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 因式分解 （1）.(x+y)(x+y-6)+9 （2）.x²-16y²-x-4y 8x-8y-3x-3y=-12,6x+6y-8x+4y=16 解方程组2(x-y)/3-x+y/4=-1 6(x-y)-4(2x-y)=16 解方程组：2(x-y)/3-x+y/4=-1 ,6(x+y)-4(2x-y)=16 2(X-Y)/3=(X+Y)/4 -1 6(X+Y)=4(2X-Y)+16解方程 2(x-y)/3-(x+y)/4=-1 (1) 6(x+y)-4(2x-y)=16 (2) 6(x+y)=4(2x-y)+16,2(x-y)/3=x+y/4-1 2(x-y)/3—x+y/4=1 6(x+y)—4(2x-y)=16 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 (2x-2y)/3-(x-y)=-1和6(x+y)-4(2x-y)=16 8（x-y)=3（x+y)-12 6（x+y)=4（2x-y)+16