This is hopefully going to be either (6x...)(x...) or (3x...)(2x...). As to which, it is just trial and error to get it. The more you do, the quicker you get at it.
So...we need 2 numbers that multiply to give 12: answers are:
1x12
2x6
3x4
So, first, have some quick mental arithmetic of multiplying one number 6 and the other by 1
Looking, i can see no combination to give 17.
So how about multiplying one number by 3 and the other by 2 to five 17? Yes, one answer: take the 4x3 combination: if we multiply the 4 by 2 and the 3 by 3 we get 8 and 9 which is 17...so:
(3x+4)(2x+3)
multiply this out to check you have indeed got the correct answer.
