How do you factor x² - 14x + 9?
1 Answer
May 13, 2016
Explanation:
One way is to complete the square and use the difference of squares identity:
a^2-b^2=(a-b)(a+b)
with
x^2-14x+9
=(x-7)^2-7^2+9
=(x-7)^2-40
=(x-7)^2-2^2*10
=(x-7)^2-(2sqrt(10))^2
=((x-7)-2sqrt(10))((x-7)+2sqrt(10))
=(x-7-2sqrt(10))(x-7+2sqrt(10))