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解方程:(x+1)(x+2)(x+3)(x+4)=120

由原方程,得(x2+5x+4)(x2+5x+6)=120.设x2+5x=y,则(y+4)(y+6)=120.即y2+10y-96=0.所以 (y-6)(y+16)=0.解得 y=6或y=-16.当y=6时,x2+5x=6,则(x+6)(x-1)=0.解得 x1=-6,x2=1;当y=-16时,x2+5x=-16,即x2+5x+16=0,该方程...

解:3(x+2)=4(x+1) 3x+6=4x+4 4x-3x=6-4 x=2 希望能够帮助你

(x+3)/(x+2)+(x+4)/(x+3)=(x+5)/(x+4)+(x+2)/(x+1) 1+1/(x+2)+1+1/(x+3)=1+1/(x+4)+1+1/(x+1) x+3+x+2/(x+2)(x+3)=x+1+x+4/(x+4)(x+1) 2x+5/(x+2)(x+3)=2x+5/(x+4)(x+1) (1)2x+5不为0 (x+2)(x+3)=(x+4)(x+1) x^2+5x+...

x(x^2+3x+2)-120=0 x^3+3x^2+2x-120=0 x^3-4x^2+7x^2-28x+30x-120=0 x^2(x-4)+7x(x-4)+30(x-4)=0 (x-4)(x^2+7x+30)=0 x-4=0, 或x^2+7x+30=0 前者得x=4, 后者无实根。 故方程只有一个实根x=4

(x-4)(x-2)(x+1)(x+3)+24=0.(x-4)(x+3)(x-2)(x+1)+24=0(x2-x-12)(x2-x-2)+24=0设y=x2-x,则(y-12)(y-2)+24=0y2-14y+24+24=0y2-14y+48=0解得:y=6或y=8,由x2-x=6解得:x1=3,x2=-2,由x2-x=8解得:x3=1+332,x4=1?332;

解: x-1/x+1+x-4/x+4=x-2/x+2+x-3/x+3 [(x-1)(x+4)+(x-4)(x+1)]/(x+1)(x+4)=[(x-2)(x+3)+(x-3)(x+2)]/(x+2)(x+3) (2x²-8)/(x+1)(x+4)=(2x²-12)/(x+2)(x+3) (x²-4)/(x²+5x+4)=(x²-6)/(x²+5x+6) (x²+5x+4)(x&...

1/(x+2)-1/(x+3)-1/(x+4)+1/(x+5)=0 1/(x+2)-1/(x+3)=1/(x+4)-1/(x+5) 1/(x+2)(x+3)=1/(x+4)(x+5) (x+2)(x+3)=(x+4)(x+5) x²+5x+6=x²+9x+20 4x=-14 x=-3.5

1+1/(x-1)+1+1/(x-4)=1+1/(x-2)+1+1/(x-3) 1/(x-1)+1/(x-4)=1/(x-2)+1/(x-3) (2x-5)/(x-1)(x-4)=(2x-5)/(x-2)(x-3) 因此2x-5=0, 得:x=5/2 或(x-1)(x-4)=(x-2)(x-3)=0, 得:x^2-5x+4=x^2-5x+6, 不符。 故只有一解为x=5/2

x+3.2=24/1.2=20 x=20-3.2=16.8

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