Answer:
Option A.
Step-by-step explanation:
Consider the given problem is
[tex]3\sqrt{\frac{7}{25}}-\sqrt{\frac{28}{25}}+\sqrt{\frac{63}{25}}[/tex]
Using the properties of radical expressions we get
[tex]3\cdot \frac{\sqrt{7}}{\sqrt{25}}-\frac{\sqrt{28}}{\sqrt{25}}+\frac{\sqrt{63}}{\sqrt{25}}[/tex] [tex][\because \sqrt{\frac{a}{b}}=\frac{\sqrt{a}}{\sqrt{b}}][/tex]
[tex]3\cdot \frac{\sqrt{7}}{\sqrt{25}}-\frac{\sqrt{4}\sqrt{7}}{\sqrt{25}}+\frac{\sqrt{9}\sqrt{7}}{\sqrt{25}}[/tex] [tex][\because \sqrt{ab}=\sqrt{a}\sqrt{b}][/tex]
[tex]3\cdot \frac{\sqrt{7}}{5}-\frac{2\sqrt{7}}{5}+\frac{3\sqrt{7}}{5}[/tex]
Taking out common factors.
[tex]\frac{\sqrt{7}}{5}(3-2+3)[/tex]
[tex]\frac{\sqrt{7}}{5}(4)[/tex]
[tex]\frac{4\sqrt{7}}{5}[/tex]
The simplified form of given expression is [tex]\frac{4}{5}\sqrt{7}[/tex]
Therefore, the correct option is A.
