Answer:
7[tex]\sqrt{7}[/tex]
Step-by-step explanation:
using the law of surds
[tex]\sqrt{a}[/tex] × [tex]\sqrt{b}[/tex] ⇔ [tex]\sqrt{ab}[/tex]
simplifying each surd
[tex]\sqrt{700}[/tex] = [tex]\sqrt{100(7)}[/tex] = [tex]\sqrt{100}[/tex] × [tex]\sqrt{7}[/tex] = 10[tex]\sqrt{7}[/tex]
[tex]\sqrt{28}[/tex] = [tex]\sqrt{4(7)}[/tex] = [tex]\sqrt{4}[/tex] × [tex]\sqrt{7}[/tex] = 2[tex]\sqrt{7}[/tex]
Putting it all together gives
10[tex]\sqrt{7}[/tex] - 2[tex]\sqrt{7}[/tex] - [tex]\sqrt{7}[/tex] = 7[tex]\sqrt{7}[/tex]
