Ta có: \(2ax^3+6ax^2+6ax+18a\)
\(=2\left[\left(ax^3+3ax^2\right)+\left(3ax+9a\right)\right]\)
\(=2a\left[x^2\left(x+3\right)+3\left(x+3\right)\right]\)
\(=2a\left(x+3\right)\left(x^2+3\right)\)
2ax3 + 6ax2 + 6ax + 18a
= 2a( x3 + 3x2 + 3x + 9 )
= 2a[ ( x3 + 3x2 ) + ( 3x + 9 ) ]
= 2a[ x2( x + 3 ) + 3( x + 3 ) ]
= 2a( x + 3 )( x2 + 3 )
= (2ax3+6ax ) + (6ax2+18a)
= 2ax (x2+3) + 6a(x2+3)
= (x2+3)(2ax + 6a)
= 2a(x2+3)(x+3)
c) 2x2(x +1) + 4x(x +1); d) 2 x(y - 1) - 2
