[tex]\sqrt{32}-\sqrt{18}=\sqrt{16*2}-\sqrt{9*2}=\sqrt{16 }*\sqrt{2}-\sqrt{9 }*\sqrt{2}=4\sqrt{2}-3\sqrt{2}=\sqrt{2}\\\\\\3\sqrt{3}+\sqrt{12}=3\sqrt{3}+\sqrt{4*3}=3\sqrt{3}+\sqrt{4 }*\sqrt{3}= 3\sqrt{3}+2\sqrt{ 3}=5\sqrt{3}\\\\\\\sqrt{45}+7\sqrt{5}=\sqrt{9*5}+7\sqrt{5}=\sqrt{9 }*\sqrt{5}+7\sqrt{5}=3\sqrt{5}+7\sqrt{5}=10\sqrt{5}\\\\\\\sqrt{50}-\sqrt{162}=\sqrt{25*2}-\sqrt{81*2 }=\sqrt{25 }*\sqrt{2}-\sqrt{81 }*\sqrt{2}=5\sqrt{2}-9\sqrt{2} =-4\sqrt{2}[/tex]
