The equation of a plane with intercepts \(a, b, c\) on the \(x, y, z\) axes respectively is:
\[
\frac{x}{a} + \frac{y}{b} + \frac{z}{c} = 1.
\]
Substitute \(a=2, b=3, c=-4\):
\[
\frac{x}{2} + \frac{y}{3} + \frac{z}{-4} = 1.
\]
Multiply both sides by 12 to clear denominators:
\[
6x + 4y - 3z = 12.
\]
Final answer:
\[
\boxed{
6x + 4y - 3z = 12.
}
\]