The statement that says deep-focus earthquakes form at subduction zones, as well as continental-continental plate boundaries, is false.
<u>Explanation:</u>
Earthquakes are classified into two major categories based on their zones of focus.
If the focus of earthquake is less than 70 kilometers deep, it is considered to be a shallow focus earthquake.
If the focus of the earthquake lies between the depth of 300 kilometers to 700 kilometers, it is categorized as deep focus earthquake.
The earthquakes that have their focus lying at a subduction zone are usually deep-focus earthquakes, whereas, the earthquakes that have their focus lying around continental-continental plate boundaries are termed as shallow-focus earthquakes.
When dealing with exponents inside and outside parenthesis with only one term in the parenthesis, you multiply the exponents. By doing this, you get 7^3x3, which is 7^9
