Question

how do I start to solve this
3y^2+17y+20=

Answer 1

is your equation equal to zero?
if so then
3y^2+17y+20=0 factors to
(y + 4)(3y + 5) = 0
y = -4 or y = -5/3

Answer 2

It just says to factor

Answer 3

then just eliminate my last step

You must have learned a method to do this

Answer 4

so if I have this problem to factor 2x^2+7xy-30y I would do this to factor it x^2+xy+7+2-30y^2

Answer 5

you probably meant to type
2x^2+7xy-30y^2 or else it won't work

the method most students appear to use these days is the method of decomposition of the middle term.
In this method you multiply the first and last number coefficients ... 2*(-30) = -60

now look for two factors of -60 which have a sum of 7
after about 3 tries I got 12 and -5
so I will break up the middle term of 7xy as -5xy+12xy

so we have
2x^2 - 5xy + 12xy - 30y^2
= x(2x - 5y) + 6y(2x - 5y)
= (2x-5y)(x+6y)

Although this seems to be the popular method taught these days, us old-timers don't use this method.
I have my own quick way where I can do about 5 questions in the time it takes somebody to do one using the above method.
(I wouldn't be at all surprised if other math tutors on here like bobpurley and drwls use the same method I do)