Đáp án:
`(x + 3)/(2x + 4)`
Giải thích các bước giải:
`\frac{x}{2x - 4} + \frac{3}{2x + 4} - \frac{6}{4 - x^2}`
`= (x)/[2(x - 2)] + 3/[2(x + 2)] - (-6)/(x^2 - 4)`
`= x/[2(x - 2)] + 3/[2(x + 2)] - (-6)/[(x + 2)(x - 2)]`
`=[x(x + 2)]/[2(x + 2)(x - 2)] + [3(x - 2)]/[2(x + 2)(x - 2)] - [(-6).2]/[2(x + 2)(x - 2)]`
`=[x(x + 2) + 3(x - 2) - (-12)]/[2(x + 2)(x - 2)] = [x^2 + 2x + 3x - 6 + 12]/[2(x + 2)(x - 2)]`
`= (x^2 + 5x + 6)/(2(x + 2)(x - 2)) = (x^2 + 2x + 3x + 6)/(2(x - 2)(x + 2))`
`= (x(x + 2) + 3(x + 2))/(2(x - 2)(x + 2)) = [(x + 2)(x + 3)]/[2(x - 2)(x + 2)] = (x + 3)/[2(x + 2)] = (x + 3)/(2x + 4)`
