[tex]7a(2a-3)+4(6a-3a^2)=14a^2-21a+24a-12a^2=2a^2+3a=a(2a+3)[/tex]
[tex]a=\cfrac{1}{2}\sqrt{3}\\2a^2+3a=2\left(\cfrac{1}{2}\sqrt{3}\right)^2+3\left(\cfrac{1}{2}\sqrt{3}\right)=2\left(\cfrac{1}{4}*3\right)+3\left(\cfrac{1}{2}\sqrt{3}\right)\\=2*\cfrac{3}{4}\right+3*\cfrac{\sqrt{3}}{2}=\cfrac{3}{2}+\cfrac{3\sqrt{3}}{2}=\cfrac{3+3\sqrt{3}}{2}[/tex]
