Which of the binomials below is a factor of this trinomial?

x2 - 5x - 36

A. x + 4
B. x - 4
C. x2 + 7
D. x - 7

Question

Which of the binomials below is a factor of this trinomial?

x2 - 5x - 36

 		A.	x + 4
 		B.	x - 4
 		C.	x2 + 7
 		D.	x - 7

welshfella · Answer

try and factor the trinomial
you need 2 numbers whose product is -36 and whose sum is -5

welshfella · Answer

what are the factors of -36 which will give -5 when added?

welshfella · Answer

Hint:-  one is -9

lilday12 · Answer

im confessed

welshfella · Answer

-36 =  -9  *  what?

welshfella · Answer

or solve the equation
-9x = -36

welshfella · Answer

these 2 numbers will then form the factors
(x + a)(x + b)

where a and b are the 2 number s:-  a = -9 and b = the one you get when you solve the equation 
-9x = -36

welshfella · Answer

-9x = -36
divide both sides by -9 
what is x ?

welshfella · Answer

what is -36 divided by -9 ?