Expand by distributing sum groups.
\[1.5x(1.5x+4y+3)-4y(1.5x+4y+3)-4.5x+12y\]
Expand by distributing terms.
\[2.25{x}^{2}+6xy+4.5x-4y(1.5x+4y+3)-4.5x+12y\]
Expand by distributing terms.
\[2.25{x}^{2}+6xy+4.5x-(6yx+16{y}^{2}+12y)-4.5x+12y\]
Remove parentheses.
\[2.25{x}^{2}+6xy+4.5x-6yx-16{y}^{2}-12y-4.5x+12y\]
Collect like terms.
\[2.25{x}^{2}+(6xy-6xy)+(4.5x-4.5x)-16{y}^{2}+(-12y+12y)\]
Simplify.
\[2.25{x}^{2}-16{y}^{2}\]
2.25*x^2-16*y^2
