ANSWER
B. 7√10
EXPLANATION
The given radical expression is:
[tex] \sqrt{40} + 2 \sqrt{10} + \sqrt{90} [/tex]
We need to remove the perfect square from the first and third term.
[tex]\sqrt{4 \times 10} + 2 \sqrt{10} + \sqrt{9 \times 10} [/tex]
We now share the radical sign to get;
[tex] \sqrt{4} \times \sqrt{10} + 2 \sqrt{10} + \sqrt{9} \times \sqrt{10} [/tex]
Simplify to get;
[tex]2\sqrt{10} + 2 \sqrt{10} + 3 \sqrt{10} [/tex]
This simplifies to
[tex]7 \sqrt{10} [/tex]
