3x 2(8-x)=24
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设(x²-1)/(x²+2x)=t则8t+3/t=118t²-11t+3=0(8t-3)(t-1)=0解得t=3/8或t=11.t=3/8(x²-1)/(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
3/x2=1/x2-x即3*2-3x=x*22x*2=3Xx=0(舍去)x=3/2
∵A=5x2+4x-1,B=-x2-3x+3,C=8-7x-6x2,∴A-B+C=(5x2+4x-1)-(-x2-3x+3)+(8-7x-6x2)=5x2+4x-1+x2+3x-3+8-7x-6x2=
等式两边同时乘以(x+3)(x-2)(x+2)就可以去分母了
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
x3-3x2-11x+8=x(x2-3x)-11x+8=x-11x+8=-10x+8
(x^2+2x+4)(x^2+2x-3)-8设m=x^2+2x+4原式=m(m-7)-8=m^2-7m-8=(m+1)(m-8)=(x^2+2x+4+1)(x^2+2x+4-8)=(x^2+2x+5)
设x2+3x=y原式=y2-2y-8=(y-4)(y+2)=(x2+3x-4)(x2+3x+2)=(x+4)(x-1)(x+2)(x+1)
(x2-x)(x2-x-8)+12解原式=(x²-x)(x²-x-8)+12=(x²-x)²-8(x²-x)+12=(x²-x-6)(x
把x2-1x2+2x=y代入原方程,得:8y+3y=11.方程两边同乘以y得:3y2-11y+8=0.故选A.
(1)(2x+1)2=3,2x+1=±3,解得:x1=−1+32,x2=−1−32;(2)x2+2x-24=0,(x+6)(x-4)=0,解得:x1=-6,x2=4;(3)2x2-4x+5=0∵b2-
(1)x²+2x-8=0x²+2x+1=8+1(x+1)²=9x+1=±3x=±3-1x1=3-1=2x2=-3-1=-4(2)x²-4=2xx²-2
(x2-x)=3(x2+x)x2-x=3x2+3xx2-3x2-x-3x=0-2x2-4x=0-2x(x+2)=0x1=0x2=-2
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
两边乘x(x+1)(x-1)2(x-1)+3(x+1)=4x2x-2+3x+3=4x5x+1=4xx=-1经检验,x=-1时分母x+1=0增根,舍去方程无解
原式=[x+2x(x-2)-x-1(x-2)2]÷x2-16x2+4x=[x2-4x(x-2)2-x2-xx(x-2)2]÷x2-16x2+4x=x-4x(x-2)2•x(x+4)(x+4)(x-4)
x²+x-1/(x²+x)=3/2两边同时乘以(x²+x)得:(x²+x)²-1=3(x²+x)/22(x²+x)²-3
x2-5x+8=0a=1,b=-5,c=8∴△=b²-4ac=(-5)²-4×1×8=25-32=-7
∵设x2+3x=y,∴原方程可化为y-20y=8,整理得y2-20=8y.故选:D.