a)\(8+\left(4x+3\right)^3\)
\(\Leftrightarrow2^3+\left(4x+3\right)^3\)
\(\Leftrightarrow\left(2+4x+3\right)\left[2^2-2.\left(4x+3\right)+\left(4x+3\right)^2\right]\)
\(\Leftrightarrow\left(5+4x\right)\left[4-8x-6+16x^2+24x+9\right]\)
\(\Leftrightarrow\left(5+4x\right)\left(16x^2+16x+7\right)\)
b)\(81-\left(9-x\right)^2\)
\(\Leftrightarrow9^2-\left(9-x\right)^2\)
\(\Leftrightarrow\left(9-9+x\right)\left(9+9-x\right)\)
\(\Leftrightarrow x\left(18-x\right)\)
a) = 2^3 + (4X-3)^3
= (2+4X-3).[2^2 - 2.(4X-3)+(4X-3)^2]
= ( -1 + 4X).(8X^2-32X+19)
b) = 9^2 - (9-X)^2
= [ 9+(9-X)].[9-(9-X)]
= ( 18-X).X
