If a factor increases 14, the calculated product will increase by 84. Then we can see the relationship between 84 and 14, and 84 divided by 14 equals 6. That is to say, when a factor increases 14, the calculated product increases by 6 14, which is 84, so we can know that one of the factors is 6.

When another factor increases 14, the calculated product increases 168. So if we look at the relationship between 168 and 14, 168 divided by 14 equals 12. That is, when this factor increases 14, the calculated product increases 12 14, that is, 168. Then you can know that another factor is 12.

Finally, two factors are found, that is, 6 and 12, and 6 times 12 equals 72. The correct product should be 72.