[tex]\sqrt{48} = \sqrt{16 \cdot 3} = \sqrt{16} \cdot \sqrt{3} = 4\sqrt{3}\\\sqrt{98} = \sqrt{49 \cdot 2} = \sqrt{49} \cdot \sqrt{2} = 7\sqrt{2}\\\sqrt{5a^4} = a^2\sqrt{5}\\\sqrt{7(2-a)^2} = \sqrt{7} \cdot \sqrt{(2 -a)^2} = |2-a|\sqrt{7} = (2-a)\sqrt{7}[/tex]