Factoring trinomials?

Question

factoring trinomials?

x^2-3x-18

(x - ?) (x -?)

i factored out the numbers to 18 but theres none with the sum of 3.

how do i go about solving this? please help there are no examples in the book.

Answer 1

  Derron,

  You started out good . You obviously know that in a trinomial the sum of the outside and inside terms must equalthe middle term. And to equal a negative term, you must multiply a positive by a negative. Now for the answer.

       x^2-3x-18

              (x+3) (x-6)

  If you multiply x*x, =

x^2. x*-6=-6,  x*3=3.  Now subtract -6+3 =-3.

I did like your question. Factoring trinomials will come in handy when you start working with radical expressions.

                                      Good luck

Answer 2

(x-6)(x+3)=0

the signs aren't necessarily negative nor positive. it can be both. :D

Answer 3

x^2 - 3x - 18

two numbers that multiply to -18 and add to -3.

(x-6)(x+3)