Given $f(x)=10-2 x$, find $f(7)$.
Answer (2)
To find f ( 7 ) for the function f ( x ) = 10 − 2 x , substitute 7 into the equation which gives f ( 7 ) = − 4 .
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Substitute x = 7 into the function: f ( 7 ) = 10 − 2 ( 7 ) .
Calculate the product: 2 ( 7 ) = 14 .
Subtract from 10: 10 − 14 = − 4 .
The final answer is − 4 .
Explanation
Understanding the problem We are given the function f ( x ) = 10 − 2 x and asked to find the value of f ( 7 ) . This means we need to substitute x = 7 into the expression for f ( x ) .
Substituting x=7 To find f ( 7 ) , we replace x with 7 in the expression for f ( x ) : f ( 7 ) = 10 − 2 ( 7 )
Simplifying the expression Now, we simplify the expression: f ( 7 ) = 10 − 14 f ( 7 ) = − 4
Final Answer Therefore, f ( 7 ) = − 4 .
Examples
In real life, functions like this can model various scenarios. For example, imagine you start with $10 and spend 2 e v ery d a y . T h e f u n c t i o n f(x) = 10 - 2x re p rese n t s h o w m u c hm o n eyyo u ha v e l e f t a f t er x d a ys . S o , f(7) = -4$ means after 7 days, you are $4 in debt.
