(4*12^{\frac{1}{2}}-3*27^{\frac{1}{2}}+2*48^{\frac{1}{2}})*3^{\frac{1}{2}}=
=4*(12*3)^{\frac{1}{2}}-3*(27*3)^{\frac{1}{2}}+2*(48*3)^{\frac{1}{2}}=
=4*36^{\frac{1}{2}}-3*81^{\frac{1}{2}}+2*144^{\frac{1}{2}}=
=4*\sqrt{36}-3*\sqrt{81}+2*\sqrt{144}=
=4*6-3*9+2*12=
=24-27+24=21