5.减去-4x等于3x2-2x-1的代数式是 .
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根据题意得:-2x+(-3x2+2x+1)=-2x-3x2+2x+1=-3x2+1.故选C.
设这个多项式为A,∵A-(-3x)=5x2-3x-5,∴A=5x2-3x-5-3x=5x2-6x-5.故选B.
由题意得:4x2-3x-5+(-2x)=4x2-5x-5.故选:A.
设X^2+3X-1=y,则原方程变形为:根号下y+8减去根号下y-8=2两边平方得:2y-2倍的根号下y^2-64=4,整理得:根号下y^2-64=y-2两边再平方得:y^2-64=y^2-4y+4即
4x^2-2x-1=0根据韦达定理:x1+x2=-(-2)/4=1/2
由2x^2-3x-4=0得:x^2-2=3x/2所以x-2/x=(x^2-2)/x=(3x/2)/x=3/2
代数式3x²-2x-1+4x=3x²+2x-1
-3-5x+4x²+-3x+2x²=6x²-8x-3
-3-5x+4x²+-3x+2x²=6x²-8x-3肯定是对的.
解分式方程输入很辛苦.经检验X=7/2是原方程的解.
4(x+y)-3(x-y)=14x+7y=14(x+y)/2+(x-y)/3=6两边同乘以6,得3(x+y)+2(x-y)=365x+y=36则x+7(36-5x)=14x=7,y=1
3x/(x+1)-(x+4)/(x^2+x)=-23x^2-(x+4)=-2(x^2+x)3x^2-x-4=-2x^2-2x5x^2+x-4=0(5x-4)(x+1)=0x1=4/5x2=-1经检验,
被减式=5x2-3x-1+(-3x),=5x2-3x-1-3x,=5x2-6x-1.故选B.
(5/12-1/4)*x=1/31/6*x=1/3x=22/3-8x=x/22/3=8.5xx=1/51
(x-1)/3-(x+2)/6=(4-x)/2等式两边同乘6得:2(x-1)-(x+2)=3(4-x)去括号:2x-2-x-2=12-3x移项:4x=16x=4
(x-1)(x-3)(x-4)(x-5)-(x-1)(x-2)(x-3)(x-5)=(x-1)(x-2)(x-4)(x-5)-(x-1)(x-2)(x-3)(x-4)(x-1)(x-3)(x-5)(x
依题意得所求代数式为5x2-3x-5+3x=5x2-5.故选B.
根据题意得:3x2-2x-1-4x=3x2-6x-1.故答案为:3x2-6x-1
6x2-xy-15y2=(2x+3y)(3x-5y)=0,所以x=-3/2y或x=5/3y
所求多项式为:(x2-3x-6)+2x=x2-x-6.故选C.