解;5x+30=3y 11x=15x+144 x= y=
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+.
先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y
5(x+y)+3(x-y)=90 5(x+y)-3(x-y)=30,解二元一次方程组
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
解方程x+y+(x+y/2)=15 3x+5y+4(x+y/2)=62
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
6(x-y)-2(x+y)=14 3(x-y)+(x+y)=5
(5x+3y)(3y-5x)-(4x-y)(4y+x)=
已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy)