17x+7y=38 7x+23y=76 怎么做?

17x+7y=38 7x+23y=76 怎么做? 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 7x:4y,x:y=( ):( 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= x+y =7 3x+y=17 {x+y=7 {3x+y=17 解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7 {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 x+2y=2x+y+1=7x-y 求：2x-y? 当x+y=2时7(x+y)一(x+y)+(x+y)=? x^2+y^2=15,x+y=7,x＞y,求x-y 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 (x-y)(x-2y)+(x-2y)(x-7y),其中X=4,Y=1.5 X+Y=7(100X+Y)-(10Y+X)=(10Y+X)-(10X+Y) 已知x+y=6,xy=7,试求x*x+y*y,x*x-y*y的值 计算3x/(x-3y)+(x+y)/(4y-x)-7y/(x-4y)=? 若x,y为正整数,且满足3x(x+y)-y(x+y)=7,求x,y 1、(-y^3)^5/y^3/ y^2+2(-y)^102、(x-y)^7/(y-x)^6+(x+y)^3/(x+y)^23、已知X^a=5,x^b=3,求X^(3a-2b)的值