How do you factor #y=x^2 - 2x - 15# ?

2 Answers
May 28, 2018

Answer:

#y=(x-5)(x+3)#

Explanation:

#"the factors of - 15 which sum to - 2 are - 5 and + 3"#

#y=(x-5)(x+3)#

May 28, 2018

Answer:

#(x-5)(x+3)#

Explanation:

First, find two numbers that have a sum of -2 (the second term) and have a product of -15 (the third term)
Multiples of 15:
1 | 15
3 | 5
#-5 * 3 = -15# and #-5 + 3 = -2#
Use this to "split the middle" of the polynomial
#x^2 - 5x + 3x - 15#
Factor
#x(x-5) + 3(x-5)#
#(x-5)(x+3)#