作业帮当2x-3y=-1时 4(3y-2x)
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原式=4x²-y²-8x²+6xy-y²+y²-6xy+9x²=5x²-y²=5-4=1
已知二元一次方程3x+4y=10,当x=0时,y=(5/2)；当x=(10/3)时,y=0{3x-2y=5.1{5x+4y=12.21式*2+2式11x=22x=2y=1/2{2x+y-z=1.1{3
(2x-y)/(x+y)=3所以(x+y)/(2x-y)=1/3原式=1/2*(2x-y)/(x+y)+1/3*(x+y)/(2x-y)=3/2+1/9=29/18
π3/4根号3-π/2--根号3
4x+3y=3k+1,2x-y=k,x=(6k+1)/10,y=(6k-4)/5,(6k+1)/10>0,(6k-4)/5>0,k>2/3
x^4-xy^3-x^3y-3x^2y+3xy^2+y^4=x^4-x^3y-3xy(x-y)+y^4-xy^3=x^3(x-y)-3xy(x-y)-y^3(x-y)=(x-y)(x^3-3xy-y^
x^4-xy^3-x^3y-3x^2y+3xy^2+y^4=（x^4-x^3y）-xy^3+y^4-3x^2y+3xy^2=x^3(x-y)-y^3(x-y)-3xy(x-y)=x^3-y^3-3xy
原试=-y-y-y.-y大概有50个-y所以答案是-50/3
|x-1|+|y+3|=0|x-1|≥0|y+3|≥0所以x-1=0,y+3=0x=1,y=-3原式=1/1*-3+1/3*-1+1/1*5+1/3*7+1/5*9+.+1/(2n-1)(2n+3)=
当x=y时2x+3y=2x+3x=45x=4x=4/5
k=3x+2y-1代入方程二得出x=-2-y把k.x等式代入方程二得出y=0k=-7x=-2
已知方程3x+y=4,当x=2时,y=(-2);当y=-1时,x=(-1)
2x-y\x+y=32x-y=3(x+y)2x-y=3x+3y3x-2x=-y-3yx=-4y2x-y/2x+2y+x+y/6x-3y=(-8y-y)/(-8y+2y)+(-4y+y)/(-24y-3
1.(x+y)/（x-2y）=3x+y=3x-6y2x=7y2x/y=7y/y=72.16的（2-x）次方=8的（x+5）次方【16=2的4次方,8=2的3次方】2的4(2-x）次方=2的3（x+5）
=（x-(x+y)）+（(x+2y)-(x+3y)）+...+(（x+98y）-(x+99y)）=-y*50=2*50=100
设y=k（x+1）+bx=1,y=4……（1）x=1/2,y=3……（2）代入原式,解得：k=2,b=0所以函数解析式为：y=2（x+1）即y=2x+2
x=4,y=17/24y=-1,x=-10再问：请问过程是什么呢？再答：x=4,代入得：-1/8+3y=2,3y=17/8得y=17/24y=-1，代入得：-1/2x-3=2,-3-2=1/2x，两边
解:(1)设y=k/(x+1)将x=4,y=1,代入,得k/(4+1)=1,解得:k=5∴y与x之间的函数关系式是y=5/(x+1).(2)设y+3=k/x将x=2,y=-3,代入,得k/2=-3+3
(x-3/16)²+|y+3/17|=0所以x-3/16=y+3/17=0x=3/16,y=-3/17所以原式=(4x²-y²-4x²+16xy-16y