若x=4 y=2 和x=-2 y=1都满足方程y=ky+b（高手进）（1）求k 和b的值（2）当x=8时,求y的值（3）当y=3时,求x的值不好意思，是y=kx+b

若x.y满足x+=4和x-y=2,求xy分之2x-y+1除以-x分之y+y分之x的值 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 2x+4y=3 -3x-2y=1 ..求x和y 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 (2x-2y)/3-(x-y)=-1和6(x+y)-4(2x-y)=16 若x*x-4y*y=-15,x+2y=3,求x和y的值 解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1kkkkkkkk 已知X和Y满足3X+4Y=2,X-Y-1/7 若y/x,1/y,1/(x+y)都有意义,则下列等式中,不一定成立的是,说明理由xy/(x^2y)=1/x1/(x-y)=(x+y)/(x^2-y^2)y/(x+1)=y^2/(xy+y)y/(x+y)=(xy-y^2)/(x^2-y^2) 三个方程组,①x-y=3 ②2（x-y+1）=4（x+y）-6 3x-8y=14 x/2+y/4=-3③3（x+y）+2（x-y）=362(x+y)-3(x-y)=24每个方程组都需要过程和结果（只是结果也行） {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 若x*x+y*y=x+y-1/2,求x,y的值如题 若x=-1/4,能否确定代数式(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)的值? 若x-y=1 化简（x+y)(x^2+y^2)(x^4+y^4)(x^8+y^8)(x^16+y^16) 若x+y=4,则多项式1/2(x+y)+4(x-y)-3（x-y）-3/2(x+y)-x+y值是（） 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=?