Suppose \(f(x)=4x+3\text{.}\)
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Letβs find \(f(2)\text{.}\) Since the \(2\) is inside the parentheses, that tells us that our input is supposed to be \(2\text{.}\) In our original formula, we replace all of the \(x\)βs with a \(2\text{.}\) Since \(f({\color{red}{x}})=4{\color{red}{x}}+3\text{,}\) we get:\begin{equation*} f({\color{red}{2}})=4({\color{red}{2}})+3 = 8+3 = 11 \end{equation*}Therefore, the answer is \(11\text{.}\)
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Letβs find \(f(-1)\text{.}\) Since the \(-1\) is inside the parentheses, that tells us that our input is supposed to be \(-1\text{.}\) In our original formula, we replace all of the \(x\)βs with a \(-1\text{.}\) Since \(f({\color{red}{x}})=4{\color{red}{x}}+3\text{,}\) we get:\begin{equation*} f({\color{red}{-1}})=4({\color{red}{-1}})+3 = -4+3 = -1 \end{equation*}Therefore, the answer is \(-1\text{.}\)