If we call g the number of green peppers and r the number of red peppers, we know that adding r to g will give us 14, or symbolically:
r + g = 14.
We also know that Ron has 8 more red peppers than green peppers - adding 8 to the number of green peppers gets us the number of red peppers, so we can represent that as
r = g + 8
Notice that the question "What number plus 8 equals r?" is really just a subtraction problem in disguise. If we start at g and go up 8, we arrive at r, but we could also start at r and go down g to arrive at 8, getting us the equation
r - g = 8
So now we've got this set of equations:
r + g = 14
r - g = 8
If adding g to r gets us 14 and subtracting g from r gets us 8, our number must be right in the middle of 14 and 8 - exactly the number 11. So
r = 11
And since r and g have to add up to 14, this forces g to be 3 since 11 + 3 = 14
We therefore have 11 red peppers and 3 green peppers.