\(A=\left(2x+3\right)\left(4x^2-6x+9\right)-2\left(4x^2-1\right)\)
\(=8x^3-12x^2+18x+12x^2-18x+27-8x^2+2\)
\(=8x^3-8x^2+29\)
ta có
\(A=\left(2x+3\right)\left(4x^2-6x+9\right)-2\left(4x^2-1\right)\)
\(A=8x^3-12x^2+18x+12x^2-18x+27-8x^2+2\)
\(A=8x^3-8x^2+29\)
Trả lời:
A = ( 2x + 3 ) ( 4x2 - 6x + 9 ) - 2 ( 4x2 - 1 )
= 8x3 - 12x2 + 18x + 12x2 - 18x + 27 - 8x2 + 2
= 8x3 - 8x2 + 29
