Math Is Fun Forum

I'm having trouble with the PSF Method of factorisation so far I have figured out that it is as follows (using the example in my book):

Question 1 (My questions are in brackets next to the area they refer to)

Factorise using the PSF Method

4y² + 4y - 3

P = Product of first and last terms = -12y² (typo)

S = Sum (what does "Sum" refer to?) or middle term = 4y

F = Factors of P that give S = 6y, -2y

∴ 4y² + 4y - 3 = 4y² + 6y - 2y - 3

= 2y(2y + 3) - 1(2y + 3) [How did it go from this: "2y(2y + 3) - 1(2y + 3)" to this "(2y + 3)(2y - 1)"?????]

=(2y + 3)(2y - 1)

Question 2 I think this question is just IMPOSSIBLE

2a² + 11a² + 5

P = 10a²

S =  11a²

F = Factors of P that give S = x, y

x = ????

y = ????