\(x^3-7x-6\)
\(=x^3-9x+2x-6+3x^2-3x^2\)
\(=\left(x^3+3x^2+2x\right)-\left(9x+3x^2+6\right)\)
\(=x\left(x^2+3x+2\right)-3\left(x^2+3x+2\right)\)
\(=\left(x^2+3x+2\right)\left(x-3\right)\)
\(=\left(x^2+2x+x+2\right)\left(x-3\right)\)
\(=\left(x+1\right)\left(x+2\right)\left(x-3\right)\)
\(x^3-7x-6\)
\(=x^3-x-6x-6\)
\(=x\left(x-1\right)\left(x+1\right)-6\left(x+1\right)\)
\(=\left(x+1\right)\left(x^2-x-6\right)\)
\(=\left(x+1\right)\left(x^2-3x+2x-6\right)\)
\(=\left(x+1\right)\left[x\left(x-3\right)+2\left(x-3\right)\right]\)
\(=\left(x+1\right)\left(x+2\right)\left(x-3\right)\)
c1 . x3 - 7x - 6
= x3 - 7x + 8 - 14
= ( x + 2)( x2 - 2x + 4) - 7( x + 2)
= ( x + 2)( x2 - 2x - 3)
= ( x + 2)( x2 + x - 3x - 3)
= ( x + 2)[ x( x + 1) - 3( x + 1 ) ]
= ( x + 1)( x + 2 )( x - 3)
c2. x3 - 7x - 6
= x3 - x - 6x - 6
= x( x2 - 1) - 6( x + 1)
= x( x + 1)(x - 1) - 6( x + 1)
= ( x + 1)( x2 - x - 6)
= ( x + 1)( x2 + 2x - 3x - 6)
= ( x + 1)[ x( x + 2) - 3( x + 2) ]
= ( x + 1)(x + 2)( x - 3)
c3 . x3 - 7x - 6
= x3 + x2 - x2 - 7x - 6
= x2( x + 1) - ( x2 + 7x + 6)
= x2( x + 1) - ( x2 + x + 6x + 6)
= x2( x + 1) - [ x( x + 1) + 6( x + 1) ]
= x2( x + 1) - ( x + 1)( x + 6)
= ( x + 1)( x2 - x - 6)
= ( x + 1)( x2 + 2x - 3x - 6)
= ( x + 1)[ x( x + 2) - 3( x + 2) ]
= ( x + 1)( x + 2)( x - 3)
x3-7x-6
x3+0x2-7x-6
=x3+x2-x2-x-6x-6
= (x3+x2)-(x2+x)-(6x+6)
=x2(x+1)-x(x+1)-6(x+1)
= (x+1)(x2-x-6)
= (x+1)(x2+2x-3x-6)
= (x+1) [x(x+2)-3(x+2)]
=(x+1) (x-3)(x+2)