Question

Which of the binomials below is a factor of this trinomial? x2 - 6x - 16

Answer 1

Well in order to get a factor you have to set the 2 x seperat and the last number too.. this will give you (x   )(x    ) they are both negative so one sign has to be a positive and the other a negative, lets find out what can we seperate the last term to, well lets see what numbers multiplied that give you -16 when adding or subtracting it gives you -6

E.J. 4 times -4 is 16 but when adding or subtracting it give you 0
lets try this 8 and 2 wehn multiplied it gives you 16 and when adding or subtracting it gives you eitehr 10 or 6!! Wow 6 that is what you need in order to get the factors of the trinomial.... SO now our factors look like (x   2)(x  8), our last step is to find out where the signs go, well if we know that the 6 is negative then we want to make our largest number a negative, this means 8 is negative so 2 will be positive so our factors now are (x+2)(x-8)... now which of these are in your choices?? well only the (x+2) so your second option would be the answer...

Hope this helps