+0  
 
+1
90
1
avatar+500 

The graph of a certain quadratic $y = ax^2 + bx + c$ is a parabola with vertex $(-4,0)$ which passes through the point $(1,-75)$. What is the value of $a$?

 Apr 13, 2021
 #1
avatar+121004 
+1

In  vertex  form  we  have  that

 

y  =a ( x + 4)^2  +  0

 

Since  ( 1, -75)  is  on the  graph, then

 

-75  = a ( 1 + 4)^2  +  0

 

-75  = a (5)^2

 

-75  = 25a

 

-75  / 25  =  a  =  - 3

 

 

cool cool cool

 Apr 13, 2021

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