Factoring by Grouping
You can get a clue from the coefficients: we have a and a , and we also have a and a . There is a proportional relationship here which can be exploited!
Factor out of the first two terms:
Then factor out of the second two terms.
Since the same quantity appears twice, we can use the distributive property to write this more simply:
Group the terms as follows:
Both groups have as a factor.