Q. What is the y-intercept of \( f(x) = 3x + 2 \)?

Answer

  1. Set x to 0.

    The y-intercept occurs where x = 0.

    \[ f(0) = 3(0) + 2 \]

  2. Calculate the result.

    \[ f(0) = 2 \]

  3. State the y-intercept.

    \[ (0, 2) \]

Detailed Explanation

Finding the (y)-intercept

To find the (y)-intercept of a linear function, we must understand its position on a coordinate plane. The (y)-intercept is the specific point where the line crosses the vertical (y)-axis.

  1. Understand the Concept

    At any point on the (y)-axis, the horizontal position is zero. This means that for any function (f(x)), the (y)-intercept always occurs when (x = 0). To find the value, we simply need to substitute zero for every (x) in the equation.

  2. Identify the Given Function

    The function provided is a linear equation in slope-intercept form:

    \(f(x) = 3x + 2\)

    In this form, \(f(x)\) represents the output value (the \(y\)-coordinate) for any given input \(x\).

  3. Substitute \(x = 0\) into the Equation

    To locate the intercept, we replace the variable \(x\) with the value \(0\):

    \(f(0) = 3(0) + 2\)

  4. Perform the Multiplication

    According to the order of operations, we perform the multiplication first. Any number multiplied by zero results in zero:

    \(3 \cdot 0 = 0\)

    Now the equation looks like this:

    \(f(0) = 0 + 2\)

  5. Simplify the Final Value

    Adding \(2\) to \(0\) gives us the final result for the function at that point:

    \(f(0) = 2\)

  6. State the Conclusion

    The \(y\)-intercept value is \(2\). When writing this as an ordered pair \((x, y)\), we combine our input of \(0\) with our result of \(2\).

Final Answer:

The (y)-intercept is (2), which corresponds to the point ((0, 2)) on the graph.

See full solution

Graph

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Frequently Asked Questions

What is the y-intercept of f(x) = 3x + 2?

The y-intercept is the point where x = 0, so f(0) = 2. The y-intercept is (0, 2) and the y-value is 2.

How do you find the y-intercept from slope-intercept form?

In y = mx + b (or f(x) = mx + b), the constant b is the y-intercept. Set x = 0 to get the y-value.

Why do we plug in x = 0 to find the y-intercept?

The y-intercept is where the graph crosses the y-axis; all points on the y-axis have x = 0, so evaluating the function at x = 0 gives that crossing point.

Is the y-intercept the same as the constant term?

Yes. In slope-intercept form f(x) = mx + b, the constant term b is the y-intercept value.

What is the x-intercept of f(x) = 3x + 2?

Set y = 0: 0 = 3x + 2, so x = -2/3. The x-intercept is (-2/3, 0).

How do you graph the line using slope and y-intercept?

Plot the y-intercept (0, 2). Use the slope 3 as rise/run = 3/1: from (0,2) go up 3 and right 1 to plot another point, then draw the line through them.

How does changing the constant term affect the graph?

Changing the constant (b) shifts the line vertically: increasing b moves the line up, decreasing b moves it down, slope unchanged.

Can line have more than one y-intercept?

No. non-vertical line crosses the y-axis exactly once. vertical line has no single y-intercept except x = 0, which lies on the y-axis and gives infinitely many points.
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