Answer:
question 8 : it is equal to 0
Question 9 : 4+5[tex]\sqrt{2}[/tex]
Step-by-step explanation:
= [tex]\sqrt{7} -\sqrt{28}\\2\sqrt{7} - \sqrt{4x7}\\2\sqrt{7} - 2\sqrt{7}\\0\\\sqrt{2} (5+\sqrt{8})\\5\sqrt{2} + \sqrt{2*8}\\5\sqrt{2} + 4\\4 + 5\sqrt{2}[/tex]
