we have
[tex]f(x)=\sqrt{4x+9} +2[/tex]
we know that
The radicand must be greater than or equal to zero
so
[tex]4x+9 \geq0 \\ 4x\geq -9 \\x\geq -\frac{9}{4} \\ x\geq -2.25[/tex]
the domain is is the interval--------> [-2.25,∞)
therefore
the answer is
[tex]4x+9 \geq0[/tex]
