SOLUTION: I understand solving equations but I am lost when it comes to finding the x-intercept of functions: Please explain and answer this problem! Thank You! y = (x - 4)(x + 2)

Algebra ->  Functions -> SOLUTION: I understand solving equations but I am lost when it comes to finding the x-intercept of functions: Please explain and answer this problem! Thank You! y = (x - 4)(x + 2)      Log On


   

Question 189452: I understand solving equations but I am lost when it comes to finding the x-intercept of functions:
Please explain and answer this problem! Thank You!
y = (x - 4)(x + 2)
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Just by looking at the graph of a function,
you can see that the x-intercepts occur
where y=0, so to find x-intercepts,
I just set y=0
y+=+%28x+-+4%29%28x+%2B+2%29
0+=+%28x+-+4%29%28x+%2B+2%29
Now I have 2 factors on the right side. If either one
equal 0, then the equation is true.
x+-+4+=+0
x+=+4
This has to be an x-intercept
x+%2B+2+=+0
x+=+-2
This has to be the other x-intercept
I'll graph the equation, too
%28x+-+4%29%28x+%2B+2%29+=+x%5E2+-+2x+-+8
+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2Cx%5E2+-+2x+-+8%29+