Find the lesser of two consecutive positive even integers whose product is 168.

Let x = the lesser even integer and let x + 2 = the greater even integer. Because product is a key word for multiplication,  the equation is x(x + 2) = 168. Multiply using the distributive property on the left side of the equation: x² + 2x = 168. Put the equation in standard form and set it equal to zero: x² + 2x - 168 = 0. Factor the trinomial: (x - 12)(x + 14) = 0. Set every factor equal to zero and solve: x - 12 = 0 or x + 14 = 0; x = 12 or x = -14. Because you are seems for a positive integer, reject the x-value of -14. Thus, the lesser positive integer would be 12.