X4 +3x³+x²-12x-20 thành nhân tử
Phân tích đa thức thành nhân tử : (4x + 1)(12x – 1)(3x + 2)(x + 1) – 4
Ta có: \(\left(4x+1\right)\left(12x-1\right)\left(3x+2\right)\left(x+1\right)-4\)
\(=\left(12x^2+8x+3x+2\right)\left(12x^2+12x-x-1\right)-4\)
\(=\left(12x^2+11x+2\right)\left(12x^2+11x-1\right)-4\)
\(=\left(12x^2+11x\right)^2+\left(12x^2+11x\right)-6\)
\(=\left(12x^2+11x+3\right)\left(12x^2+11x-2\right)\)
Phân tích đa thức thành nhân tử
\(3x-\sqrt{x}-20\)
Phân tích đa thức thành nhân tử : x4 + x3 + 2x2 + x + 1
\(=\left(x^4+x^3+x^2\right)+\left(x^2+x+1\right)\)
\(=x^2\left(x^2+x+1\right)+\left(x^2+x+1\right)\)
\(=\left(x^2+1\right)\left(x^2+x+1\right)\)
\(x^4+x^3+2x^2+x+1\)
\(=x^4+x^3+x^2+x^2+x+1\)
\(=\left(x^2+x+1\right)\left(x^2+1\right)\)
Phân tích đa thức thành nhân tử : x5 – x4 – 30x3
\(x^5-x^4-30x^3=x^3\left(x^2-x-30\right)=x^3\left(x-6\right)\left(x+5\right)\)
\(x^5-x^4-30x^2=x^2\left(x^2-x-30\right)=x^2\left(x+5\right)\left(x-6\right)\)
Phân tích đa thức thành nhân tử : x6 - x4 + 2x3 + 2x2
\(=\left(x^6+2x^5+x^4\right)-2\left(x^5+2x^4+x^3\right)+2\left(x^4+2x^3+x^2\right)\)
\(=x^2\left(x^2+x\right)^2-2x\left(x^2+x\right)^2+2\left(x^2+x\right)^2\)
\(=\left(x^2+x\right)^2\left(x^2-2x+2\right)\)
\(=x^2\left(x+1\right)^2\left(x^2-2x+2\right)\)
\(x^6-x^4+2x^3+2x^2\)
\(=x^2\left(x^4-x^2+2x+2\right)\)
\(=x^2\left[x^2\left(x-1\right)\left(x+1\right)+2\left(x+1\right)\right]\)
\(=x^2\left(x+1\right)\left(x^3-x^2+2\right)\)
Phân tích đa thức thành nhân tử : x4 + 6x3 + 11x2 + 6x + 1
\(x^4+6x^3+11x^2+6x+1\)
\(=x^4+3x^3+x^2+3x^3+9x^2+3x+x^2+3x+1\)
\(=\left(x^2+3x+1\right)^2\)
Phân tích đa thức thành nhân tử : x4 + 6x3 + 7x2 – 6x + 1
\(x^4+6x^3+7x^2-6x+1\)
\(=x^4-2x^2+1+6x^3+9x^2-6x\)
\(=\left(x^2-1\right)^2+6x\left(x^2-1\right)+9x^2\)
\(=\left(x^2+3x-1\right)^2\)
1. phân tích thành nhân tử : x3 - 12x + 1 - 12x2
\(x^3-12x^2-12x+1=x^3+x^2-13x^2-13x+x+1=x^2\left(x+1\right)-13x\left(x+1\right)+x+1=\left(x+1\right)\left(x^2-13x+1\right)\)
\(=\left(x^3+1\right)-12x\left(x+1\right)\)
= \(\left(x+1\right)\left(x^2-x+1\right)-12x\left(x+1\right)\)
= \(\left(x+1\right)\left(x^2-13x+1\right)\)
= \(\left(x+1\right)\left(x-\frac{13+\sqrt{165}}{2}\right)\left(x-\frac{13-\sqrt{165}}{2}\right)\)
Phân tích đa thức thành nhân tử :
(x2 + 6x – 1)2 + 2x2 + x4 + 2(x2 + 6x – 1)(x2 + 1)
\(\left(x^2+6x-1\right)^2+2x^2+x^4+2\left(x^2+6x-1\right)\left(x^2+1\right)\)
\(\left(x^2+6x-1\right)^2+2\left(x^2+6x-1\right)\left(x^2+1\right)+\left(x^2+1\right)^2-1=\left(x^2+6x-1+x^2+1\right)^2-1=\left(2x^2+6x\right)^2-1=\left(2x^2+6x-1\right)\left(2x^2+6x+1\right)\)
\(\left(x^2+6x-1\right)^2+2\left(x^2+6x-1\right)\left(x^2+1\right)+x^4+2x^2\)
\(=\left(x^2+6x-1\right)\left(x^2+6x-1+2x^2+2\right)+x^4+2x^2\)
\(=\left(x^2+6x-1\right)\left(3x^2+6x+1\right)+x^4+2x^2\)
\(=\left(2x^2+6x-1\right)\left(2x^2+6x+1\right)\)