Questions: If f(x) is a linear function, f(-3)=-4, and f(3)=-5, find an equation for f(x)
f(x)=
Transcript text: If $f(x)$ is a linear function, $f(-3)=-4$, and $f(3)=-5$, find an equation for $f(x)$
\[
f(x)=
\]
$\square$
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Solution
Solution Steps
Step 1: Determine the slope of the linear function
A linear function can be expressed in the form:
\[
f(x) = mx + b
\]
where \( m \) is the slope and \( b \) is the y-intercept.
Given two points on the line, \( (-3, -4) \) and \( (3, -5) \), the slope \( m \) can be calculated using the formula:
\[
m = \frac{y_2 - y_1}{x_2 - x_1}
\]
Substituting the given points:
\[
m = \frac{-5 - (-4)}{3 - (-3)} = \frac{-1}{6} = -\frac{1}{6}
\]
Step 2: Find the y-intercept \( b \)
Using the slope \( m = -\frac{1}{6} \) and one of the points, say \( (-3, -4) \), substitute into the linear equation to solve for \( b \):
\[
-4 = -\frac{1}{6}(-3) + b
\]
Simplify:
\[
-4 = \frac{1}{2} + b
\]
Subtract \( \frac{1}{2} \) from both sides:
\[
b = -4 - \frac{1}{2} = -\frac{9}{2}
\]
Step 3: Write the equation of the linear function
Substitute \( m = -\frac{1}{6} \) and \( b = -\frac{9}{2} \) into the linear equation:
\[
f(x) = -\frac{1}{6}x - \frac{9}{2}
\]