Question 987416: Im not sure if this is the right section, but I'm asked to factor a quadratic trinomial:
3x^2-5x+2
Up until now, for these quadratic trinomials I've been using the method where you place the variable in parentheses: (x )(x )
and now find two numbers that multiple to give the outside term (+2), and add to give the middle term (-5x). The problem is that +2 seems to give me very little factors to work with (1, 2) (-1,-2), and these do not add up to -5, so I'm stuck, and probably missing something extremely obvious.
Answer by josgarithmetic(39630)   (Show Source):
You can put this solution on YOUR website! The method to decompose the trinomial into two binomial factors still works for your given trinomial. There may be a few different combination trials to check.
 ;
The possible factors for the constant term ignoring sings will be 2 and 1.
The possible coefficient factors for the leading, square term will be 3 and 1, again, IGNORING signs.
Decompositions to try:
(3x 1)(x 2) not effective for getting the linear and the constant term right
(3x 2)(x 1) THIS one should be effective
You want the linear term to be negative and the constant term be positive.
(3x-2)(x-1)
(3x-2)(x+1)
(3x+2)(x+1)
(3x+2)(x-1)
WHICH OF THEM WORKS?
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