The PSF method is a simple way to solve quadratics if you can't solve it in your head.
Take the equation: x^2+5x+6 (where a=1,b=5,c=6)
P: (product) you multiply 'a' and 'c'. result = 6.
S: (sum) you find the sum of 2 factors of 6 which give the value of 'b'. in this case +3,+2.
F...