3.5x 2.6x=12.2解方程
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6x²+85x-250=0(2x-5)(3x+50)=02x-5=0或3x+50=0x1=5/2x2=-50/3
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
(1)由韦达定理,x1+x2=-2/3,x1x2=-2于是,x1^3+x2^3=(x1+x2)(x1²-x1x2+x2²)=-2/3[(x1+x2)²-3x1x2]=-1
x=7(x²-x+1)7x²-7x+7=x7x²+7=8x两边平方49x4+98x²+49=64x²两边减去49x²49x4+49x&sup
根据韦达定理,X1+X2=5,X1*X2=-6,X1方+x2方=(X1+X2)方-2*X1*X2=37(x1-X2)方=(X1+X2)方-4*X1*X2=49
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
x/x²-3x+1=1/5x²-3x+1=5xx²+1=8xx+1/x=8平方x²+2+1/x²=64x²+1/x²=62x
1、y=2x²-6x由题,y=2(x²-3x)=2[x²-3x+(3/2)^2-(3/2)^2]=2(x-3/2)^2-2*9/4=2(x-3/2)^2-9/2所以:y=
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
焦点为:(1,0)设AB方程为:y=k(x-1)y1+y2=k(x1+x2)-2k=6k-2k=4ky1^2=4x1,y2^2=4x2y1^2-y2^2=4(x1-x2)(y1-y2)/(x1-x2)
令x²+x=t原方程变为t+1=6/tt²+t-6=0(t+3)(t-2)=0则t=2或-31)x²+x=2x²+x-2=0(x+2)(x-1)=0x=-2或x
由韦达定理x1+x2=-(-6/2)=3x1x2=3/2x1²+x2²=(x1+x2)²-2x1x2=9-3=6
x+1/x=4两边乘xx²+1=4x两边平方x^4+2x²+1=16x²两边减去x²x^4+x²+1=15x²所以x²/(x^+x
由韦达定理得x1+x2=3,x1*x2=3/2则x1²+x2²=(x1+x2)²-2x1*x2=9-3=6x1³+x2³=(x1+x2)(x1
由x2(x的二次方)+x-1=0得出x2(x的二次方)+x=1那么:x3(x的三次方)+2x2(2x的二次方)-3=x3(x的三次方)+x2(x的二次方)+x2(x的二次方)-3=x【x2(x的二次方
x2-x+1分之x=6分之一x²-x+1=6xx²+1=7xx+1x=7(x+1/x)²=7²x²+x+1/x²=49x²+1/x
x²+1/x²=3两边平方x的四次方+2+1/x的四次方=9x的四次方+1/x的四次方=7
原方程化为√[(5x-1)(x-1)]+√[(5x-1)(x+2)]=5x-1,由此知5x-1≥0,于是,由第一个根式知x-1≥0,即x≥1,所以,原方程可化为√(x-1)+√(x+2)=√(5x-1