Question

解方程：x^2+x分之7-x^2-1分之6=x-x^2分之3

Answer 1

(x^2+x)分之7-(x^2-1)分之6=(x-x^2)分之3

7/(x^2+x)-6/(x^2-1)=3/(x-x^2)

7/[x(x+1)]-6/[x(x-1)]=-3/[x(x-1)]

分母最小公倍数是x(x-1)(x+1)

等号左右同乘x(x-1)(x+1)得

7(x-1)-6(x+1)=-3(x+1)

7(x-1)-3(x+1)=0

7x-7-3x-3=0

4x-10=0

4x=10

x=5/2