Which of the following equations represents a linear function?

2x − 4 = 6
x = −2
y equals one half times x squared
y equals two thirds times x plus 4

1 answer

To determine which of the given equations represents a linear function, we can analyze each one:

  1. \(2x - 4 = 6\): This equation can be simplified to find \(x\).

    • Adding 4 to both sides yields \(2x = 10\),
    • Dividing by 2 gives \(x = 5\).
    • This is not a linear function because it does not define \(y\) in terms of \(x\).
  2. \(x = -2\): This equation represents a vertical line at \(x = -2\).

    • It does not represent a function in the traditional sense (where each \(x\) has a single \(y\)), but it can be considered a linear equation.
  3. \(y = \frac{1}{2}x^2\): This equation represents a parabolic function (quadratic function), not a linear function.

  4. \(y = \frac{2}{3}x + 4\): This is the standard form of a linear equation (in slope-intercept form \(y = mx + b\)), where \(m = \frac{2}{3}\) (the slope) and \(b = 4\) (the y-intercept).

From this analysis, the equation that represents a linear function is:

\(y = \frac{2}{3}x + 4\).