Question

21.Find the product:
( a + b + c - d )( a - b - c -d ​

Answer 1

Answer:

a^2 + 2ad - b^2 + 2cb + 2bd

Step-by-step explanation:

a^2 - ab - ac - ad - ba - b^2 - bc - bd + ca - cb - c^2 - cd - da - db - dc - d^2

=: a^2 + 2ad - b^2 + 2cb + 2bd

Answer 2

Answer:

$a {}^{2} + 2ad - b{}^{2} - 2bc + d + d {}^{2}$

THIS IS THE ANSWER FOR YOU......HOPE IT HELPS YOU DEAR....HAVE A NICE DAY....