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44 votes
44 votes
If f(x) = 7 + 2x and g(x) = 5x - 2, find fg(7).693703-693-703

User Pratik Pitale
by
2.5k points

1 Answer

23 votes
23 votes

SOLUTION:

Step 1 :

In this question, we are meant to find the value of:


f\text{ g ( 7 )}
\begin{gathered} \text{If f(x ) = 7 + 2x } \\ \text{and g ( x ) = 5 x - 2} \end{gathered}

Step 2 :


\begin{gathered} \text{Given fg ( x ) = f ( g ( x ) ) } \\ \operatorname{Re}call\text{ that f ( x ) = 7 + 2 x } \\ f\text{ ( g( x ) ) = f ( 5 x- 2 )} \\ \text{Then f ( x ) = 7 + 2x } \\ f\text{ ( 5 x- 2 ) = 7 + 2 ( 5 x -2 )} \\ \end{gathered}
\begin{gathered} f\text{ }(\text{ 5 x - 2 ) = 7 + 10 x - 4} \\ f\text{ ( 5 x- 2 ) = 10 x + 3} \\ f\text{ ( g ( 7 ) )= 10 ( 7 ) + 3} \\ f\text{ ( g ( 7 ) })\text{ = 70 + 3} \\ f\text{ ( g ( 7 ) ) = 73} \end{gathered}

CONCLUSION:

The value of fg ( 7 ) = 73.

User Wesam Abdallah
by
3.0k points
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