Which of the binomials below is a factor of this trinomial? x2 - 7x - 8 A.x - 4 B.x + 2 C.x + 4 D.x - 8

Question

tkhunny · Answer

Have you considered factoring the Trinomial?

x^2 - 7x - 8 = (x + ___)(x - ___)

Fill in the blanks with factors of 8.

8 = 1 * 8
8 = 2 * 4

anonymous · Answer

so would the answer be x+4? @tkhunny

tkhunny · Answer

You tell me.  Did you factor it?

tkhunny · Answer

Let's see.   4 * 8 = 32.  Nope!  That is not a proper factorization.

x^2 - 7x - 8 = (x + ___)(x - ___)

Fill in the blanks with factors of 8. 

8 = 1 * 8
8 = 2 * 4

It's either +1 and -8 or -1 and +8 or -2 and +4 or +2 and -4.  No other possibilities.

anonymous · Answer

wait would it be (x+1)(x-8)? so it would be D? @tkhunny

tkhunny · Answer

Perfect.  Now the question is simple.