## Precalculus (6th Edition) Blitzer

$c$
The terms of the given trinomial have no common factors so techinique (a) will not work. The polynomial has only three terms so factoring by grouping (technique b) will not work. The polynomial is not a difference of two square so technique (d) will not work. The polynomial is not a perfect square trinomial so technique (e). The polynomial is not a sum or a difference of two cubes so techniques (f) and (g) will not work. The given trinomial can be factored by trial and error. Using this method gives $4x^2+8x+3=(2x+1)(2x+3).$