(3x+2x)

$$\\(3x+2)^2-(5x-2)(2x+3)\\
=9x^2+12x+4-(10x^2+15x-4x-6)\\
=9x^2+12x+4-(10x^2+11x-6)\\
=9x^2+12x+4-10x^2-11x+6\\
=9x^2-10x^2+12x-11x+4+6\\
=\;-x^2+x+10\\$$

.

expand=>  6*x+4-(10x)^2-15*x+4*x+6

simplify=> -(10*x)^2+5*x+10