The x-intercepts are the ordered pairs that have values of 0 for the y-values.
Various methods exist:
1) Graphing
2) Quadratic Formula
3) Factoring
Let's factor. The coefficient of the x2
term is 1
so we can look at the constant term, −8
, and find its factors that add up to, 2
, the coefficient of the x
term.
Factors of -8:
1+(−8)=−7
, Does not work
(−1)+8=7
, Does not work
2+(−4)=−2
, Does not work
(−2)+4=2
, Works because it is 2
0=(x−2)⋅(x+4)
Now set each factor equal to zero.
(x−2)=0
x=2
(x+4)=0
x=−4
The x-intercepts are (2,0)
and (−4,0).
