Answer:
Explanation:
Okay so what we have to do is expand using the FOIL technique, or First Outer Inner Last.
So:
Our first terms are a and a so multiplied together we get
![a^(2)](https://img.qammunity.org/2020/formulas/mathematics/college/otbqkld68jlclq6m2mg2lstej7svz0m4b4.png)
Then we have outer which would be -b times a or -ab
Then we have inner which would be b times a or ab
And then we have our last term which would be b times b or
![-b^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/r6m86nm1xdtkmgck3fwjzhkuzl700a1ytj.png)
Now we add all of our terms together to get:
![a^(2) -ab + ab - b^(2) \\](https://img.qammunity.org/2020/formulas/mathematics/high-school/avrbvnhs3ri2k824pfx8usn2azy37hofg8.png)
Which simplifies to
![a^(2) - b^(2)](https://img.qammunity.org/2020/formulas/mathematics/high-school/3rfu94rzdpzztfuk32x9nac818tdulxg7i.png)