$\displaystyle \begin{array}{{>{\displaystyle}l}} 3\sqrt{2} +\sqrt{8} +5\sqrt{32} \ \\ =3\sqrt{2} +2\sqrt{2} +5.4\sqrt{2} \ \\ =\sqrt{2}( 3+2+20)\\ =25\sqrt{2} \ \\ b)\sqrt{3} -2\sqrt{75} +3\sqrt{12}\\ =\sqrt{3} -2.5\sqrt{3} +3.2\sqrt{3}\\ =\sqrt{3}( 1-10+6)\\ =-3\sqrt{3} \ \\ c) 2\sqrt{18} -3\sqrt{50} +4\sqrt{72}\\ =2.3\sqrt{2} -3.5\sqrt{2} +4.6\sqrt{2}\\ =\sqrt{2}( 6-15+24)\\ =15\sqrt{2} \ \\ d) 5\sqrt{48} -2\sqrt{75} -3\sqrt{147}\\ =5.4\sqrt{3} -2.5\sqrt{3} -3.7\sqrt{3}\\ =\sqrt{3}( 20-10-21)\\ =-11\sqrt{3} \end{array}$
