SOLUTION: f(x)16x^2+40x+25 what is the y-intercept and what is the x-intercept

Algebra ->  Rational-functions -> SOLUTION: f(x)16x^2+40x+25 what is the y-intercept and what is the x-intercept      Log On


   

Question 138711: f(x)16x^2+40x+25
what is the y-intercept and what is the x-intercept
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The y-intercept occurs where x=0
f%28x%29+=+16x%5E2+%2B+40x+%2B+25
Make x=0
f%280%29+=+25
(0,25) is the y-intercept
The x-intercept occurs where y=0
16x%5E2+%2B+40x+%2B+25+=+0
divide both sides by 16
x%5E2+%2B+%285%2F2%29x+%2B+%285%2F4%29%5E2+=+0
The left side is a perfect square
%28x+%2B+%285%2F4%29%29%5E2+=+0
Take the square root of both sides
%2B%28x+%2B+%285%2F4%29%29+=+0
x+=+-%285%2F4%29
and
-%28x+%2B+%285%2F4%29%29+=+0
x+=+-%285%2F4%29
So, the x-intercept is (-5/4,0)