## Intermediate Algebra (12th Edition)

$\bf{\text{Solution Outline:}}$ To factor the given expression, $9x^2+4xy-2y^2 ,$ find two numbers whose product is $ac$ and whose sum is $b$ in the quadratic expression $ax^2+bx+c.$ Use these $2$ numbers to decompose the middle term of the given quadratic expression and then use factoring by grouping. $\bf{\text{Solution Details:}}$ To factor the trinomial expression above, note that the value of $ac$ is $9(-2)=-18$ and the value of $b$ is $4 .$ The possible pairs of integers whose product is $ac$ are \begin{array}{l}\require{cancel} \{1,-18\}, \{2,-9\}, \{3,-6\}, \\ \{-1,18\}, \{-2,9\}, \{-3,6\} .\end{array} Among these pairs, none gives a sum of $b.$ Hence, the given expression is $\text{ not factorable with integer coefficients .}$