+0  
 
0
42
3
avatar

The graph of y=x^2+bx+c passes through points (0, 5),(1, 10), (2, 19) and . Find a+b+c.

 Dec 26, 2020
 #1
avatar
+1

When x = 0   you find   c = 5

 

x^2 + bx + 5       now, when x = 1

1 + b + 5 = 10      so b = 4

 

x^2 + 4x + 5        

       Hmmmmm    something seems amiss     when x = 2  y should be 17 , not 19   

                                 did you enter your Q correctly?

 Dec 26, 2020
 #2
avatar+114325 
+1

I'm assuming that  you left off the "a" in your original question

 

Guest is correct....c   = 5

 

And we have  this system

 

a + b + 5   =10    ⇒   a  +  b   =   5  ⇒    b = 5  -  a       (1)

4a  + 2b + 5  = 19  ⇒  4a  + 2b  =  14    (2)

 

Sub (1) into (2)   and we have

 

4a  + 2 (5 - a)   =  14

4a  + 10 - 2a  =  14

2a  =  4

a   =  2

 

And  b  =  5  -  2   = 3

 

So 

 

a + b  +  c   =   2   +   3    +   5   =   10

 

 

cool cool cool

CPhill  Dec 26, 2020
 #3
avatar
0

thank you my gods

 Dec 26, 2020

14 Online Users

avatar
avatar