Answer:
[tex]11\sqrt{2} - 5\sqrt{7}[/tex]
Option (A) is the correct answer.
Step-by-step explanation:
[tex]9\sqrt{2} - 3\sqrt{7} + \sqrt{8} - \sqrt{28}[/tex]
Now, [tex]\sqrt{8} = \sqrt{2 \times 2 \times 2} = 2\sqrt{2}[/tex]
[tex]\sqrt{28} = \sqrt{2 \times 2 \times 7} = 2\sqrt{7}[/tex]
∴ [tex]9\sqrt{2} - 3\sqrt{7} + \sqrt{8} - \sqrt{28}[/tex]
= [tex]9\sqrt{2} - 3\sqrt{7} + 2\sqrt{2} - 2\sqrt{7}[/tex]
= [tex]9\sqrt{2} + 2\sqrt{2} - 3\sqrt{7} - 2\sqrt{7}[/tex]
= [tex]11\sqrt{2} - 5\sqrt{7}[/tex]
Therefore option (a) is the correct answer.