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\(x^3+1-x^2-x\)
\(=\left(x+1\right)\left(x^2+x+1\right)-x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2+x+1-x\right)\)
\(=\left(x+1\right)\left(x^2+1\right)\)
đáp án
=( x + 1 ) . ( x2 + 1 )
hok tốt
okazki
\(x^3+1-x^2-x\)
\(=\left(x+1\right)\left(x^2-x+1\right)-x\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-2x+1\right)\)
\(=\left(x+1\right)\left(x-1\right)^2\)
\(x+y-x^3-y^3\)
\(=\left(x+y\right)-\left(x+y\right)\left(x^2-xy+y^2\right)\)
\(=\left(x+y\right)\left(1-x^2+xy-y^2\right)\)
\(4x^2-28=0\)
\(\Leftrightarrow4\left(x^2-7\right)=0\)
\(\Leftrightarrow x^2-7=0\)
\(\Leftrightarrow x^2=7\)
\(\Leftrightarrow x=\pm\sqrt{7}\)
\(3x\left(x-5\right)-x\left(4+3x\right)=43\)
\(\Leftrightarrow3x^2-15x-4x-3x^2=43\)
\(\Leftrightarrow-19x=43\)
\(\Leftrightarrow x=\frac{-43}{19}\)
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
TL:
\(4x^2-y^2+4x+1\)
\(=\left(2x-1\right)^2-y^2\)
\(=\left(2x-1+y\right)\left(2x-1-y\right)\)
\(x^3-x+y^3-y\)
\(=\left(x+y\right)\left(x^2-xy+x^2\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x^2-xy+x^2-1\right)\)
a) \(x+6x^2\)
\(=x\left(1+6x\right)\)
b)\(5x\left(x-2\right)-\left(2-x\right)\)
\(=5x\left(x-2\right)+\left(x-2\right)\)
\(=\left(x-2\right)\left(5x+1\right)\)