A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 5 years ago
how to determine a & b valuesin the equation: y=ax^2 +bx4 if the vertex is located at (2,1) Please help!
anonymous
 5 years ago
how to determine a & b valuesin the equation: y=ax^2 +bx4 if the vertex is located at (2,1) Please help!

This Question is Closed

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1did you enter in 2 for x and 1 for y

Hero
 5 years ago
Best ResponseYou've already chosen the best response.11 = a(2)^2 +(4a)(2)  4

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1so a has different value too

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1myininaya, how come you just can't do things the normal way?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so you cant just sub 2 into one equation and 1 into another, andthe other number equal zero? or does that not mke any sense?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0I'm just a little confused by the math you did above..lol

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1myininaya likes to go overboard with her methods

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1ok hero but there are two possible outcomes

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1Not if you do it the way I did. I used direct substitution

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1We have a parabola concave up and also concave down at vertex

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1Here I will do it the way I told you to

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0Im familar with substitution , just not the way shown above im only in gr 10 so mabye thats why i dont get yours?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0^did you make 2 equations and then substitutions?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.01 = a(2)^2 +(4a)(2)  4 :this is what you did, why did you sub 4a into the equation? is there a more strait forward way to do this? :)

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1myininaya, if you use the direct substitution method, you wouldn't have to worry about getting hung up like that. The parabola opens upward or downward depending on the value of a. Since I calculated a to be negative, I'm pretty sure it opens downward and there is only one possibility

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1I replace b with 4a because b = 4a

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1I also replaced x = 2 and y = 1

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1Which are all of the known values

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1according to x = b/2a, there's only one possible a

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0alright im still a bit confused but thanks for your help!! :)

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1\[1=a(2)^2+b(2)4\] \[1=4a2b4 => 3=4a2b\] We also know the vertex which is (2,1) \[y=a(xh)^2+k\] we also know h=2 and k=1 so we have \[y=a(x+2)^21=a(x^2+4x+4)1=ax^2+4ax+4a1=ax^2+4ax+(4a1)\] \[=>4a=b , 4=4a1\] \[=>3=b2b=> 3=b=> b=3\] if b=3 then a=3/4 hmmm how do we get the other possibility ok so maybe there is only one lol

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1There's only one possibility because there's only one a value that would work in order to get both sides equal for x = b/2a

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1if a was squared, then there would be two possibilities

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1I didn't think about the yintercept

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1The parabola has vertex (2,1) and 4 is lower so this graph will be concave down

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1dw:1327278866372:dw

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1we can't not have it concave up is has to come to that 4

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1so my bad hero you win this one

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1I don't win many so I will savor this :P

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1hey lady do you understand what i did up there?

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0A bit lol but thanks!

Hero
 5 years ago
Best ResponseYou've already chosen the best response.1mya likes to confuse people then ask if they understand

myininaya
 5 years ago
Best ResponseYou've already chosen the best response.1you also have to use the vertex form like i did to find another equation or two

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0im still pretty confused but i can move on to a different qestion on my assignment lol thanks for the help on this one tho :)
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.