Question

solve the equation the square root of the quantity x plus 3 plus 4 equals 5 for the variable.

Answer 1

Domain:  expression under square root is greater or equal than zero.

x+3>0
x>-3

Then:

$\sqrt{x+3}}+4=5 \qquad |-4 \\ \\ \sqrt{x+3}=1 \qquad |(...)^2 \\ \\ x+3=1 \\ \\ x=-2 \in D$

So the answer is x=-2