Answer:
Please see the attached picture for the full solution.
*From the 4th line of the 1st image, you could also expand it using
(a +b)²= a² +2ab +b² and
(a -b)²= a² -2ab +b².
When squaring a fraction, square both the denominator and numerator.
➣(a/b)²= a²/b²
