由方程组3(x+y)-2(x-y)=11,4(x+y)+3(x-y)=9可知,x+y等于?x-y等于?x为?y为?
若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于
现规定一种新运算:x*y=(x+y)-(x-y),其中x,y为有理数,则x*y+(x+y)*(x-y)等于多少
x/4+2等于x,x=多少.y/5等于y-3,Y=多少
已知关于x,y的方程组{2x+3y=k,3x-4y=k+11}的解x,y之和等于3,求k
解方程组x+y/3=x-y/4 2x+3y=11
|x|=3 |y|=5 |x-y|=|x|+|y| 求 X+Y和 X-Y 等于多少
解方程组 {3(x+y)-4(x-y)=11 {2(x-y)+5(x+y)=27全过程、快
解方程组 {3(x+y)-4(x-y)=11 {2(x-y)+5(x+y)=27
4x+5y=105,2x+3y=178,x,y等于
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
y-3x=2,y-5x=4,y-7x=6,y-9x=8,y-11x=0方程组,
若3X=4Y,那么X;Y等于