将(x-y)看成一个因式,合并式子
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设3x+5=y,则原方程可化为y²-4y+3=0,解得y1=1,y2=3,则当3x+5=1时,x=-4/3;当3x+5=3时,x=-2/3
可以设另一因式为ax+by,则(3x-y)(ax+by)=3ax²+(3b-a)xy-by²=mx²+5xy-2y²所以b=2,3b-a=5,3a=m解得a=1
y=-2x+3笨那笨.怎么听旳课啊.我初三我们一次函数学完咯可简单
2(x+y)-3(x-y)²+3(x+y)+4(x-y)²=(2+3)(x+y)+(-3+4)(x-y)²=5(x+y)+(x-y)²
若将x-y看成一个整体,合并多项式(x-y)+3(x-y)-2(y-x),可得6(x-y)
X-Y看成一个整数,合并多项式(X-Y)²+3(X-Y)-2(Y-X),可得?(X-Y)²+3(X-Y)-2(Y-X),=(X-Y)²+3(X-Y)+2(x-y),=(X
(x-y)2+3(x-y)-2(y-x)=2(x-y)+3(x-y)+2(x-y)=7(x-y)
将多项式x²+kx+8分解因式后,一个因式是x+4,则另一个因式是x+2
由于8=4×2,依题设知x²+kx+8=(x+4)(x+2)故另一个因式是x+2
∵xy和(x+y)构成127∴xy=12,x+y=7∴x=3,y=4(反过来也一样)将其入x²-xy+y²(我错了,好像不用解出来.)原式=(x+y)²-3xy=49-9
4(a+b)的2次方+2(a+b)-7(a+b)+3(a+b)的二次方=(4+3)(a+b)²+(2-7)(a+b)=7(a+b)²-5(a+b)
因为n(n+1)(n+2)(n+3)=(n²+3n)(n²+3n+2)=[(n²+3n+1)-1][(n²+3n+1)+1]=(n²+3n+1)^2-
1.(a+b)(4+2-1)=5(a+b)2.(x-y)[3(x-y)-7+8(x-y)+6)]=(x-y)[3(x-y)-1]
(1)4(a+b)+2(a+b)-(a+b)=(4+2-1)(a+b)=5(a+b)
3(a-b)^2-2(a-b)+10(b-a)^2-(b-a)=3(a-b)^2-2(a-b)+10(a-b)^2+(a-b)=13(a-b)^2-(a+b)说明:因为(a-b)^2=(b-a)^2,
1.M=-2X^2+MX-15=x^2-2x-15=(x-5)(x+3)2.y=5x+(36/x^2)3.6/(X^2-9)=(-1/(X+3))+(1/(X-3))=(1/(x-3))-(1/(x+
原式=2[(x+y)^2-4(x-y)^2]=2(x+y+2x-2y)(x+y-2x+2y)=2(3x-y)(-x+3y)=2(-3x^2+10xy-3y^2)=-6x^2+20xy-6y^2
1.-(x+y);2.-5x-1;3.28;
(1)5(a+b)(2)11(x-y)^2-(x+y)小学数学么...
(x-3)的平方-2(x-3)-5(x-3)平方+(x-3)=-4(x-3)²-(x-3)再问:A、-4(x-3)平方+(x-3)B4(x-3)平方-x(x-3)C4(x-3)平方-(x-3