解方程:7⼀(x^2)-4⼀(x-x^2)=(8-x^2)⼀(x^2-1)+1

2024-12-16 17:46:06
推荐回答(2个)
回答1:

7/x^2 - 4/(x-x^2) = (8-x^2)/(x^2-1) + 1
7/x^2 + 4/(x^2-x) = (8-x^2)/(x^2-1) + 1
7/x^2 + 4/{x(x-1)} = (8-x^2)/{(x+1)(x-1)} + 1
两边同乘以x^2(x+1)(x-1):
7(x+1)(x-1) + 4x(x+1) = (8-x^2)x^2 + x^2(x+1)(x-1)
7x^2 - 7 + 4x^2 + 4x = 8x^2 - x^4 + x^4 - x^2
4x^2 + 4x - 7 = 0
4(x+1/2)^2 = 7+1
(x+1/2)^2 = 2
x = -1/2 ±√2

回答2:

7/(x^2)-4/(x-x^2)=(8-x^2)/(x^2-1)+1
7(x^2-1)+4x(x+1)=(8-x^2)*x^2+x^2(x^2-1)
7x^2-7+4x^2+4x=8x^2-x^4+x^4-x^2
4x^2+4x-7=0
(2x+1)^2=8
2x+1=±2√2
x=±√2-1/2