a)
(x + 1)/(2x - 2) + (-2x)/(x² - 1)
(x² + 2x + 1)/[2(x - 1)(x + 1)] + (-4x)/[2(x - 1)(x + 1)]
(x² - 2x + 1)/[2(x - 1)(x + 1)]
(x - 1)²/[2(x - 1)(x + 1)]
(x - 1)/[2(x + 1)]
b)
(2x)/(x² + 4x + 4) + (x + 1)/(x + 2) + (2 - x)/(x + 2)²
Phân tích mẫu thức:
x² + 4x + 4 = (x + 2)²
(2x)/(x + 2)² + (x² + 3x + 2)/(x + 2)² + (2 - x)/(x + 2)² = (2x + x² + 3x + 2 + 2 - x)/(x + 2)² = (x² + 4x + 4)/(x + 2)²
(x² + 4x + 4)/(x + 2)²
(x + 2)²/(x + 2)²
1
c)
(2x - 1)/(x - 1) - (x - 2)/(x - 1)
(2x - 1)/(x - 1) - (x - 2)/(x - 1)
(2x - 1 - x + 2)/(x - 1)
(x + 1)/(x - 1)
e)
(x³ - 1)/(x² - x) - (x³ + 1)/(x² + x)
[(x² + x + 1)(x+1) - (x² - x + 1)(x-1)]/[x(x-1)(x+1)]
[x³ + 2x² + 2x + 1 - (x³ -2x² + 2x - 1)]/[x(x-1)(x+1)]
[x³ + 2x² + 2x + 1 - x³ + 2x² - 2x + 1]/[x(x-1)(x+1)]
(4x² + 2)/[x(x-1)(x+1)]
2(2x² + 1)/[x(x²-1)]
f)
(x² + y²)/(x² - y²) - y²/(xy - y²) - x²/(x² - xy)
g)
(2x² - x)/(x - 1) + (x + 1)/(1 - x) + (2 - x²)/(x - 1)
(2x² - x)/(x - 1) - (x + 1)/(x - 1) + (2 - x²)/(x - 1)
(2x² - x - x - 1 + 2 - x²)/(x - 1)
(x² - 2x + 1)/(x - 1)
(x - 1)²/(x - 1)
x - 1