Your question is a little unclear but I'm assuming you mean either 6^2+24x=0 or 6^2-24x=0
To solve this you need to separate common numbers. 24 equals 4 times 6 and since the first half of the equation has a 6 in it, you can group them together. They also share an x so you can take one out.
It would look something like this 6x(x-4)=0 or 6x(x+4)=0. Now you set each part of the equation to zero and solve.
6x=0 and (x-4)=0 or (x+4)=0
The answers you will get are 0, and 4 (or negative 4)