Answer
$-1 \le x \le 6$
Work Step by Step
The equation involves only the variable x.
Notice that the value of $x^2-4x$ (which is represented by the parabola) is less than or equal to the value of $x+6$ (which is represented by the line) in the interval $-1 \le x \le 6$
Therefore, the solution to the given inequality is: $-1 \le x \le 6$.