\(=6\left(4x^2-9y^2+6y-1\right)\)
\(=6\left[\left(2x\right)^2-\left(3y-1\right)^2\right]\)
\(=6\left(2x-3y+1\right)\left(2x+3y-1\right)\)
\(24x^2+36y-54y^2-6\)
\(=6\left(4x^2+6y-9y^2-1\right)\)
\(=6\left[4x^2-\left(9y^2-6y+1\right)\right]\)
\(=6\cdot\left[\left(2x\right)^2-\left(3y-1\right)^2\right]\)
\(=6\left(2x-3y+1\right)\left(2x+3y-1\right)\)