Lets note the change between each of the numbers in the sequence:
-2 --> 6 ---> 14
Next, make an equation between each of these numbers with x being the change between them
-2+ x = 6, 6 + x = 14 .
Now, solve each of these equations:
-2+ x = 6 --> -2+ x = 6 <em>Add 2 on both sides to cancel out the -2 </em>--> <em>x = 8</em>
6+ x = 14 --> -2+ x = 6 Minus <em>6 on both sides to cancel out the 6 </em>--> <em>x = 8</em>
<u><em>From this, the common difference will be 8.</em></u>
Hope that helps.