Chapter 3: Problem 62
If \(f(x)=8 x-9\), evaluate \(f\left(\frac{3}{5}\right)\).
Short Answer
Expert verified
The evaluated value is \( \frac{-21}{5} \).
Step by step solution
01
Understand the given function
The function provided is \( f(x) = 8x - 9 \). This means for any value of \( x \), you can find the corresponding value of \( f(x) \) by substituting \( x \) into the function.
02
Substitute the given value into the function
Substitute \( x = \frac{3}{5} \) into the function \( f(x) = 8x - 9 \). This gives us \( f\left( \frac{3}{5} \right) = 8 \left( \frac{3}{5} \right) - 9 \).
03
Simplify the expression
Multiply \( 8 \) by \( \frac{3}{5} \) to get \( \frac{24}{5} \). Now the expression is \( f\left( \frac{3}{5} \right) = \frac{24}{5} - 9 \).
04
Subtract to get the final answer
Convert \( 9 \) to a fraction with a denominator of \( 5 \), which is \( \frac{45}{5} \), and subtract from \( \frac{24}{5} \). This results in \( f\left( \frac{3}{5} \right) = \frac{24}{5} - \frac{45}{5} = \frac{24 - 45}{5} = \frac{-21}{5} \).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Substitute Values in Functions
First, understand the concept of a function. In mathematics, a function is a rule that assigns exactly one value to each input. For instance, our function is given by the equation \( f(x) = 8x - 9 \). This means, whatever value of \( x \) you put in, it will calculate the corresponding \( f(x) \) by following this rule.
To evaluate \( f \left( \frac{3}{5} \right) \), follow these steps:
To evaluate \( f \left( \frac{3}{5} \right) \), follow these steps:
- Identify the value to substitute. Here, you need to substitute \( x = \frac{3}{5} \) into \( f(x) \).
- Replace every instance of \( x \) in the function with \( \frac{3}{5} \).
Simplify Expressions
Simplifying expressions involves combining like terms and performing arithmetic operations to get the simplest form of the expression. In our problem, you need to simplify \( 8 \times \frac{3}{5} - 9 \).
Here’s how to do that:
To continue, we need to handle the fraction arithmetic.
Here’s how to do that:
- First, multiply \( 8 \) by \( \frac{3}{5} \). The rule to multiply a whole number by a fraction is straightforward: multiply the numerator by the whole number and place it over the original denominator. This gives us \( \frac{24}{5} \).
To continue, we need to handle the fraction arithmetic.
Fraction Arithmetic
Dealing with fractions can be tricky, but it's just a matter of following some basic rules. To subtract a whole number from a fraction, perform these steps:
Remember, practicing these steps with different numbers can further solidify your understanding of evaluating functions, simplifying expressions, and performing fraction arithmetic.
- Convert the whole number to a fraction. For \( 9 \), we change it to \( \frac{45}{5} \) because both numbers must have the same denominator.
- Now, subtract the two fractions: \( \frac{24}{5} - \frac{45}{5} \).
- Subtract the numerators while keeping the denominator the same. This gives you \( \frac{24 - 45}{5} = \frac{-21}{5} \).
Remember, practicing these steps with different numbers can further solidify your understanding of evaluating functions, simplifying expressions, and performing fraction arithmetic.