Dadas as funções $f$ e $g$

\[\begin{array}{*{20}{c}}   {f\left( x \right) = 2x + 3}&{\text{e}}&{g\left( x \right) =  – {x^2} + 5} \end{array}\]

1. $\left( {f \circ f} \right)\left( 1 \right) = f\left( {f\left( 1 \right)} \right) = f\left( {2 \times 1 + 3} \right) = f\left( 5 \right) = 2 \times 5 + 3 = 13$
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2. $\left( {g \circ g} \right)\left( 2 \right) = g\left( {g\left( 2 \right)} \right) = g\left( { – {2^2} + 5} \right) = g\left( 1 \right) =  – {1^2} + 5 = 4$
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3. $\left( {f \circ g} \right)\left( 2 \right) = f\left( {g\left( 2 \right)} \right) = f\left( { – {2^2} + 5} \right) = f\left( 1 \right) = 2 \times 1 + 3 = 5$
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4. $\left( {g \circ f} \right)\left( 2 \right) = g\left( {f\left( 2 \right)} \right) = g\left( {2 \times 2 + 3} \right) = g\left( 7 \right) =  – {7^2} + 5 =  – 44$