计算6x2-7x-20-搜答案-搜狗做题网

1/(x-3)-6/(x2-9)-(x-1)/(6+2x)=1/(x-3)-6/[(x+3)(x-3)]-(x-1)/[2(x+3)]=[2x+6-6*2-(x-1)*(x-3)]/[2(x+3)(x

后面的x²＋11x－708有误吧!再问：没有题目就这样能不能帮我再答：那我就试试：原式为：1/x2+x+1/x2+3x+2+1/x2+5x+6+1/x2+7x+12+1/x2+9x+20=5

2/(x2-x)+6/(1-x2)=7/(x2+x)2/x(x-1)-6/(x-1)(x+1)=7/x(x+1)[x*(x-1)*(x+1)]*[2/x(x-1)-6/(x-1)(x+1)]=[7/x

原式=[1/(x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)]×(x+4)(x+5)=[1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/(x+3)-1/(x

（1）原式=x(x+9)x(x+3)+(x+3)(x−3)(x+3)2=x+9x+3+x−3x+3=2(x+3)x+3=2；（2）原式=-x−2x−1÷x2−4x−1=-x−2x−1•x−1(x+2)

1/(x²+3x+2)=[(x+2)-(x+1)]/(x+1)(x+2)=1/(x+1)-1/(x+2)同理1/(x²+5x+6)=1/(x+2)-1/(x+3)1/(x²

1/(x2-5x+6)-1/(4x-x2-3)-1/(3x-x2-2)=1/(x2-5x+6)+1/(x2-4x+3)+1/(x2-3x+2)=1/(x-2)(x-3)+1/(x-3)(x-1)+1/

7/(X2+X)+3/(X2-X)=6/(X2-X),去分母,等式两端同时乘X(X+1)(X-1):7(X-1)+3(X+1)=6(X+1),7X-7+3X+3=6X+6,7X+3X-6X=6+7-3

(x^2+x+2)(x^2+x+7)-6=(x^2+x)^2+9(x^2+x)+14-6=(x^2+x)^2+9(x^2+x)+8=(x^2+x+1)(x^2+x+8)

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(x2-7x+6)(x2-x-6)+56=(x-6)(x-1)(x-3)(x+2)+56=[(x-6)(x+2)][(x-1)(x-3)]+56=(x^2-4x-12)(x^2-4x+3)+56=(x

令y=x²+5x+6原式=y(y+2x)-3x²=y²+2xy-3x²然后利用十字相乘y²+2xy-3x²y-xy3x=(y-x)(y+3x

(x²-1)/(x²-2x+1)÷(x²+x)/(x-1)=(x+1)(x-1)/(x-1)²乘(x-1)/x(x+1)=1/x

7/（x+x2）-3/（x-x2）=6/（x2-1）两边同乘以x(x+1)(x-1),得7(x-1)+3(x+1)=6x7x-7+3x+3=6x10x-6x=3-74x=-4x=-1经检验x=-1是增

原式=-x+2x2+5+4x2-3-6x=6x2-7x+2．

－6x^2+6再答：6x2我以为是12了．．．再答：如果6x2是6*x^2那么答案－6

(x/x2-9)-(1/x2+6x+9)=x/(x+3)(x-3)-1/(x+3)²=[x(x+3)-(x-3)]/(x-3)(x+3)²=[x²+3x-x+3]/(x-

（x+a)(x+b)=x^2+(a+b)x+a

x+y=2再问：过程再答：x2-y2=(x+y)(x-y)=3(x+y)=6则x+y=2