$$f : ( 1.5 x - 4 y ) ( 1.5 x + 4 y + 3 ) - 4.5 x + 12 y$$
$\frac{12f+16fy-192y^{2}+144xy+6fx-27x^{2}}{4\left(\frac{3x}{2}-4y\right)}$
$-\frac{27x^{2}-6fx-144xy+192y^{2}-16fy-12f}{4\left(\frac{3x}{2}-4y\right)}$
