Câu hỏi của trương ngọc ánh

Question

a. [(3x-2).(x+1) - (2x+5).( x^2 - 1)] : (x + 1)

Mashiro Shiina · Accepted Answer

$a=\dfrac{\left(3x-2\right)\left(x+1\right)-\left(2x+5\right)\left(x^2-1\right)}{x+1}$

$a=\dfrac{\left(3x-2\right)\left(x+1\right)-\left(2x+5\right)\left(x+1\right)\left(x-1\right)}{x+1}$

$a=\dfrac{\left(x+1\right)\left[\left(3x-2\right)-\left(2x+5\right)\left(x-1\right)\right]}{x+1}$

$a=3x-2-\left(2x+5\right)\left(x-1\right)$

$a=3x-2-2x\left(x-1\right)+5\left(x-1\right)$

$a=3x-2-2x^2+2x+5x-5$

$a=10x-7-2x^2$Câu trả lời: $a=\dfrac{\left(3x-2\right)\left(x+1\right)-\left(2x+5\right)\left(x^2-1\right)}{x+1}$

$a=\dfrac{\left(3x-2\right)\left(x+1\right)-\left(2x+5\right)\left(x+1\right)\left(x-1\right)}{x+1}$

$a=\dfrac{\left(x+1\right)\left[\left(3x-2\right)-\left(2x+5\right)\left(x-1\right)\right]}{x+1}$

$a=3x-2-\left(2x+5\right)\left(x-1\right)$

$a=3x-2-2x\left(x-1\right)+5\left(x-1\right)$

$a=3x-2-2x^2+2x+5x-5$

$a=10x-7-2x^2$

Bài 3: Rút gọn phân thức