(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+7x+12)
(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+7x+12)
原式=1/（x+1)(x+2)+1/(x+2)(x+3)+1/(x+3)(x+4)
=1/(x+1)-1/(x+2)+1/(x+2)-1/（x+3)+1/(x+3)-1/(x+4)
=1/(x+1)-1/(x+4)
=(x+4-x-1)/(x²+5x+4)
=3/(x²+5x+4)
祝你开心
(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+7x+12)+(1/x^2+9x+20)
1/x^2-3x+2-1/x^2-5x+6-1/x^2-7x+12-1/x^2-9x+20
=1/(x-1)(x-2)-1/(x-2)(x-3)-1/(x-3)(x-4)-1/(x-4)(x-5)
=1/(x-1)-1/(x-2)-[1/(x-2)-1/(x-3)+1/(x-3)-1/(x-4)+1/(x-4)-1/(x-5)]
=1/(x-1)-1/(x-2)-1/(x-2)+1/(x-5)
=1/(x-1)-2/(x-2)+1/(x-5)
(此题中间的三个减号是否有错？）
1/x^2-5x+6+1/x^2-7x+12+1/x^2-3x+2
(-15x^3+20x^2+3)/x^2
化简 (1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+4x+3) （化积为差，裂项相消）
(1/x^2+3x+2)+(1/x^2+5x+6)+(1/x^2+4x+3)
=1/[(x+1)(x+2)]+1/(x+2)(x+3)]+1/[(x+1)(x+3)]
=1/(x+1)-1/(x+2)+1/(x+2)-1/(x+3)+1/2[1/(x+1)-1/(x+3)]
=[1/(x+1)-1/(x+3)]×3/2
=3/(x²+4x+3)
化简：1/x^2-3x+2+1/x^2-x +1/x^2+x+1/x^2+3x+2
1/x^2-3x+2+1/x^2-x +1/x^2+x+1/x^2+3x+2
=1/（x-2）(x-1)+1/x(x-1)+1/x(x+1)+1/(x+2)(x+1)
=(x+x-2)/x(x-2)(x-1)+(x+2+x)/x(x+1)(x+2)
=2/x(x-2)+2/x(x+2)
=(2x+4+2x-4)/x(x+2)(x-2)
=4/(x+2)(x-2)
=4/(x^2-4)
1/X²+3X+2 +1/X²+5X+6 +1/X²+7X+12 +1/X²+9X+20
你好！
原式= 1/(x+1)(x+2) + 1/(x+2)(x+3) + 1/(x+3)(x+4) + 1/(x+4)(x+5)
= (x+3+x+1) / [ (x+1)(x+2)(x+3) ] + (x+5+x+3) / [ (x+3)(x+4)(x+5)]
= 2 / [(x+1)(x+3)] + 2/ [(x+3)(x+5)]
= [2(x+5)+2(x+1)] / [ (x+1)(x+3)(x+5)]
= (4x+12) / [ (x+1)(x+3)(x+5)]
= 4 / [ (x+1)(x+5)]
1/3(3x+10-7x/2)-1/6(2x+2x+2/3)=x/2-1
1/3(3x+10-7x/2)-1/6(2x+2x+2/3)=x/2-1
6x +20 - 7x - 4x - 2/3 = 3x - 6
8x = 26 - 2/3 = 76 /3
x = 19 / 6
1/2-x=1/x-2-6-x/3x^2-12
您好：
1/2-x=1/x-2-6-x/3x^2-12 两边乘3（x+2）（x-2）
-3(x+3)=3(x+2)-(6-x)
-3x-9=3x+6-6+x
-3x-9=4x
4x+3x=-9
x=-9/7
不明白，可以追问如有帮助，记得采纳，
谢谢 祝学习进步！
