a: \(=\dfrac{2x^3+x^2-6x^2-3x+2x+1}{2x+1}=2x^2-3x+1\)
b: \(=\dfrac{x^3+2x^2-2x^2-4x+2x+4}{x+2}=x^2-2x+2\)
d: \(=\dfrac{\left(x^2-1\right)\left(x^2+1\right)-2x\left(x^2-1\right)}{x^2-1}=\left(x-1\right)^2\)
h: \(=\dfrac{x^3+x^2-3x^2-3x+8x+8}{x+1}=x^2-3x+8\)
\(c,\)
\(\left(6x^3-19x^2+23x-12\right):\left(2x-3\right)\)
\(=\left(6x^3-10x^2-9x^2+8x+15x-12\right):\left(2x-3\right)\)
\(=\left[\left(6x^3-10x^2+8x\right)-\left(9x^2-15x+12\right)\right]:\left(2x-3\right)\)
\(=\left[2x\left(3x^2-5x+4\right)-3\left(3x^2-5x+4\right)\right]:\left(2x-3\right)\)
\(=\left[\left(3x^2-5x+4\right)\left(2x-3\right)\right]:\left(2x-3\right)\)
\(=3x^2-5x+4\)
\(e,\)
\(\left(6x^3-5x^2+4x-1\right):\left(2x^2-x+1\right)\)
\(=\left(6x^3-3x^2-2x^2+3x+x-1\right):\left(2x^2-x+1\right)\)
\(=\left[\left(6x^3-3x^2+3x\right)-\left(2x^2-x+1\right)\right]:\left(2x^2-x+1\right)\)
\(=\left[3x\left(2x^2-x+1\right)-\left(2x^2-x+1\right)\right]:\left(2x^2-x+1\right)\)
\(=\left[\left(2x^2-x+1\right)\left(3x-1\right)\right]:\left(2x^2-x+1\right)\)
\(=3x-1\)
\(f,\)
\(\left(x^3-2x^2-5x+6\right):\left(x+2\right)\)
\(=\left(x^3-4x^2+2x^2+3x-8x+6\right):\left(x+2\right)\)
\(=\left[\left(x^3+2x^2\right)-\left(4x^2+8x\right)+\left(3x+6\right)\right]\)
\(=\left[x^2\left(x+2\right)-4x\left(x+2\right)+3\left(x+2\right)\right]\)
\(=\left[\left(x+2\right)\left(x^2-4x+3\right)\right]:\left(x+2\right)\)
\(=x^2-4x+3\)
\(g,\)
\(\left(x^3-2x^2-5x+6\right):\left(x+2\right)\)
\(=\left(x^3+2x^2-4x^2-8x+3x+6\right):\left(x+2\right)\)
\(=\left[\left(x^3+2x^2\right)-\left(4x^2+8x\right)+\left(3x+6\right)\right]:\left(x+2\right)\)
\(=\left[x^2\left(x+2\right)-4x\left(x+2\right)+3\left(x+2\right)\right]:\left(x+2\right)\)
\(=\left[\left(x+2\right)\left(x^2-4x+3\right)\right]:\left(x+2\right)\)
\(=x^2-4x+3\)
giúp mik câu 5-8 ạ mik cám ơn các bạn, mong mn giúp đỡ vì nay mik thi r, gvbm mới cho đề hồi hôm qua ạ ,mik khá là sốc gvbm có thể kì thị lớp mik như vậy ạ
