Question

Help me please thanks

Answer 1

= 3 + √(9+7) - √(3*9)
= 3 + √16 - √27
= 3 + 4 - 3√3
= 7 - 3√3

answer
B.   7 - 3√3

Answer 2

Do both variables. 

Here, we have 3 + √16-√21.

The square root of 16 is 4. (3 + 4 - √21)

Simplify. 7 - √21.

Square root of 21 is 4.5

7 - 4.5 = 2.4

Round. 2