( 1, ∞) is the domain of (b o a)(x)
A function is defined as a relation between a set of inputs having one output each.
According to the question,
[tex]a(x) = 3x + 1 \\\\b (x) =\sqrt{x+4}[/tex]
To find the domain of the composite function,
[tex](b o x) (x) = b(a(x))\\\\(b o x) (x) = b(a(3x-1))\\\\(b o x) (x) = \sqrt{3x+ 1 -4} \\\\(b o x) (x) = \sqrt{3x -3}\\\\[/tex]
Therefore,
[tex]3x - 3 \geq 0\\3x \geq 3\\x \geq 1\\\\[/tex]
Hence , [ 1, ∞ ] is is the domain of (b o a)(x).
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