posted by Rae Rae .
The last one which you were asking where the b came from I typed the wrong problem sorry.
the problem is 49-a^2b^2
Is the answer: (7+ab)-(7ab)
the difference of two squares
(sqrt first + sqrt second)(sqrt first - sqrt second)
Check these by multiplying them out.
How about answering your own question.
will I get 49-a^2b^2 if I simplify (7+ab)-(7ab) ??
now try (7 + ab)(7 - ab)
Thank you now I understand how to check them to see if there right. Thanks Damon, and thanks Reiny.