Answer:
3[tex]\sqrt{2}[/tex]
Step-by-step explanation:
Using the rule of radicals
[tex]\sqrt{a}[/tex] × [tex]\sqrt{b}[/tex] ⇔ [tex]\sqrt{ab}[/tex]
Simplify the given radicals
[tex]\sqrt{50}[/tex]
= [tex]\sqrt{25(2)}[/tex]
= [tex]\sqrt{25}[/tex] × [tex]\sqrt{2}[/tex]
= 5[tex]\sqrt{2}[/tex]
------------------------
[tex]\sqrt{72}[/tex]
= [tex]\sqrt{36(2)}[/tex]
= [tex]\sqrt{36}[/tex] × [tex]\sqrt{2}[/tex]
= 6[tex]\sqrt{2}[/tex]
-----------------------
[tex]\sqrt{128}[/tex]
= [tex]\sqrt{64(2)}[/tex]
= [tex]\sqrt{64}[/tex] × [tex]\sqrt{2}[/tex]
= 8[tex]\sqrt{2}[/tex]
Then
[tex]\sqrt{50}[/tex] + [tex]\sqrt{72}[/tex] - [tex]\sqrt{128}[/tex]
= 5[tex]\sqrt{2}[/tex] + 6[tex]\sqrt{2}[/tex] - 8[tex]\sqrt{2}[/tex]
= 11[tex]\sqrt{2}[/tex] - 8[tex]\sqrt{2}[/tex]
= 3[tex]\sqrt{2}[/tex]
