00:01
In this problem we have been asked to prove that the product of two integers, one of the form 3k1 plus 2 and the other of the form 3k2 plus 2, is of the form 3k3 plus 1, where k1, k2, and k3 are integers.
00:13
So the product of two integers, one is of the form 3k1 plus 2, the other one is of the form 3k2 plus 2.
00:21
What we're going to do is we're going to multiply these two to find the product.
00:25
So we have 3k1 times 3k2, so that will be 9k1k2, plus 3k1 times 2, so we have 6k1, plus 2 times 3k2, so we have 6k2, and then plus 2 times plus 2, that is plus 4.
00:44
Now what we're going to do is we're going to leave the first three terms unchanged, and we have a 4 at the end.
00:51
Instead of 4, we're going to write 3 plus 1, because 3 plus 1 is 4.
00:55
And the reason we do that is because we're going to factor out 3.
00:59
So we're going to factor out 3 from the first four terms over here...