Question 733357
to solve all quadratic equations by factorising the first thing is to look for factor pairs of the constant term, in this case that is +20.
factors of +20 are: (remember that both of these could be positive or both could be negative, because negative multiplied by negative gives a positive answer)
plus/minus 1 and 20:
plus/minus 2 and 10:
Plus/minus 4 and 5.
Now we look to see if any of those factor pairs can be added to make the coefficient of the p term (that's the number in front of the p) which is +9.
Obviously the factor pair we need are plus 4 and plus 5 because +4 +(+5) = +9
Now we get two brackets and put an p in both and one of the factors in each bracket
Like this
(p+4)(p+5)
There's the answer
{{{p^2+9p+20=(p+4)(p+5)}}}