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\(-6x^2\left(x+5\right)^2-\left(x-3\right)^2+\left(x^2-2\right)\left(2x^2+1\right)-4x^2\left(3x-4\right)^2\)
\(=-6x^2\left(x^2+10x+25\right)-\left(x^2-6x+9\right)+\left(2x^4-3x^2-2\right)-4x^2\left(9x^2-24x+16\right)\)
\(=-6x^4-60x^3-150x^2-x^2+6x-9+2x^4-3x^2-2-36x^4+96x^3-64x^2\)
\(=-40x^4+36x^3-218x^2+6x-11\)
(đã thử lại)
\(=-6x^2\left(x^2+10x+25\right)-x^2+6x-9+2x^4-3x^2-2-4x^2\left(9x^2-24x+16\right)\)
\(=-6x^4-60x^3-150x^2-x^2+6x-9+2x^4-3x^2-2-4x^2\left(9x^2-24x+16\right)\)
\(=-4x^4-60x^3-154x^2+6x-11-36x^4+96x^3-64x^2\)
\(=-40x^4+36x^3-218x^2+6x-11\)
1: \(=3\left(16x^2y^2-\left(x-y\right)^2\right)\)
\(=3\left(4xy-x+y\right)\left(4xy+x-y\right)\)
2: =(x-2)(x-4)
5: =-(x^2+2x-15)
=-(x+5)(x-3)
a) = x3 + 9x2 + 27x + 27 - 9x3 -6x2 - x + 8x3 +1 -3x2 =54
26x +28 = 54
26x = 54-28 = 26
x = 1
b) = x3 - 9x2 + 27x -27 - x3 +27 +6x2 + 12x + 6 +3x2 = -33
39x +6 = -33
39x = -33-6 = -39
x = -1
\(\left(-3x-2\right)^2+\left(3x+5\right)\left(5-3x\right)=-7\)
\(\Leftrightarrow9x^2+12x+4+15x-9x^2+25-15x=-7\)
\(\Leftrightarrow12x+36=0\Leftrightarrow x=-3\)
\(\left(x+2\right)\left(x^2+2x+2\right)-x\left(x-8\right)^2=\left(4x-3\right)\left(4x+3\right)\)
\(\Leftrightarrow x^3+2x^2+2x+2x^2+4x+4-x\left(x^2-16x+64\right)=16x^2-9\)
\(\Leftrightarrow x^3+4x^2+6x+4-x^3+16x^2-64=16x^2-9\)
\(\Leftrightarrow4x^2+6x-51=0\)
\(\cdot\Delta=6^2-4.4.\left(-51\right)=852\)
Vậy pt có 2 nghiệm phân biệt
\(x_1=\frac{-6+\sqrt{852}}{8}\);\(x_2=\frac{-6-\sqrt{852}}{8}\)
1: \(=3\left[16x^2y^2-\left(x^2-2xy+y^2\right)\right]\)
\(=3\left[\left(4xy\right)^2-\left(x-y\right)^2\right]\)
\(=3\left(4xy-x+y\right)\left(4xy+x-y\right)\)
3: \(=4\left(x^4+x^2y^2-2y^4\right)\)
\(=4\left(x^4+2x^2y^2-x^2y^2-2y^4\right)\)
\(=4\left[x^2\left(x^2+2y^2\right)-y^2\left(x^2+2y^2\right)\right]\)
\(=4\left(x^2+2y^2\right)\left(x-y\right)\left(x+y\right)\)
4: \(=-\left(x^2+2x-15\right)=-\left(x+5\right)\left(x-3\right)\)
5: =(x-1)(3x-1)
Giải:
1) \(\left(x-6\right)\left(x^2+6x+36\right)-\left(x+4\right)^3=\left(x-2\right)^3+\left(x+5\right)\left(x^2-10x+25\right)-\left(2x^3+6x^2\right)\)
\(\Leftrightarrow x^3-216-\left(x^3+12x^2+48x+64\right)=x^3-6x^2+12x-8+x^3+125-2x^3-6x^2\)
\(\Leftrightarrow x^3-216-x^3-12x^2-48x-64=x^3-6x^2+12x-8+x^3+125-2x^3-6x^2\)
\(\Leftrightarrow-280-12x^2-48x=-12x^2+12x+117\)
\(\Leftrightarrow-280-48x-12x-117=0\)
\(\Leftrightarrow-397-60x=0\)
\(\Leftrightarrow-60x=397\)
\(\Leftrightarrow x=-\dfrac{397}{60}\)
Vậy ...
2) \(\left(2x+3\right)^3-\left(2x+5\right)\left(4x^2-10x+25\right)=\left(6x-1\right)^2-\left(x-2\right)\left(x^2+2x+4\right)+x^3\)
\(\Leftrightarrow8x^3+36x^2+54x+27-\left(8x^3+125\right)=36x^2-12x+1-\left(x^3-8\right)+x^3\)
\(\Leftrightarrow8x^3+36x^2+54x+27-8x^3-125=36x^2-12x+1-x^3+8+x^3\)
\(\Leftrightarrow54x-98=-12x+9\)
\(\Leftrightarrow54x+12x=9+98\)
\(\Leftrightarrow66x=107\)
\(\Leftrightarrow x=\dfrac{107}{66}\)
Vậy ...
Bạn nhân giản rồi thu gọn
Kết quả: \(-40x^4+36x^3-218x^2+6x-11\)