SOLUTION: Hello! I am having a hard time understanding the way much of the online math resources are written. They all seem to be using a very mathematical sort of dialect (thus we can see.

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Hello! I am having a hard time understanding the way much of the online math resources are written. They all seem to be using a very mathematical sort of dialect (thus we can see.      Log On


   

Question 652586: Hello! I am having a hard time understanding the way much of the online math resources are written. They all seem to be using a very mathematical sort of dialect (thus we can see... or to find x we need to complete a square, with no word on how one might accomplish this "completion of a square"), which in my opinion is counterproductive--the very people needing help with math are the very ones who won't understand the language! Anyways, that's a bit long-winded, so here's the problem:
"If a parabola opening to the left has a vertex at (-1, -3) and passes through point (-3,-2), what is the coefficient of the squared term in the parabola's equation?"
Thanks very much for reading this!
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

Parabolas:

the vertex form of a Parabola opening up(a>0) or down(a<0)is: y=a%28x-h%29%5E2+%2Bk 

where(h,k) is the vertex 

the vertex form of a Parabola opening right(a>0) or left(a<0)is: x=a%28y-k%29%5E2+%2Bh

 where(h,k) is the vertex 

Question states***

parabola opening to the left has a vertex at (-1, -3)

 x = a(y+3) - 1 , a <0   |Using  Pt(-3,-2) to solve for a

 -3 = a(-2 + 3)^2 - 1

 -2 = a

 x = -2(y+3) - 1

the coefficient of the squared term is -2