Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
countonme123
Group Title
Solve quadratic equation by completing the square. Check both roots.
problem below
 2 years ago
 2 years ago
countonme123 Group Title
Solve quadratic equation by completing the square. Check both roots. problem below
 2 years ago
 2 years ago

This Question is Closed

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
\[2x^212x +16=0\]
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
please explain each step I am having trouble with it
 2 years ago

Sonita Group TitleBest ResponseYou've already chosen the best response.0
2(x^26x+8)=0 2[(x4)(x2)]=0
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
please do explain why you do each step
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.0
1st step Factor out 2. Second step What 2 numbers add to the end value, and multiply to the middle value?
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.0
Those 2 values are then put into the brackets as you see them.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.0
And here, the signs of positive and negatives are reversed because when you solve for x individually, x4=0 x=4. Ok?
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
ok but there is supposed to be two answers
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
4 is one of them
 2 years ago

petewe Group TitleBest ResponseYou've already chosen the best response.1
dw:1339466532153:dw
 2 years ago

petewe Group TitleBest ResponseYou've already chosen the best response.1
dw:1339466562615:dw
 2 years ago

petewe Group TitleBest ResponseYou've already chosen the best response.1
dw:1339466604939:dw
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.0
eh, you might be might be making this more difficult than it actually is
 2 years ago

petewe Group TitleBest ResponseYou've already chosen the best response.1
I did what the question asked. Solve quadratic equation by completing the square.
 2 years ago

NotTim Group TitleBest ResponseYou've already chosen the best response.0
ay. missed that. thx.
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
You made a small mistake. The 8 should also be multiplied by 2.
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
Just 2 rather.
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
Leaving you with\[2(x^26x+99+8)=2((x3)^21)=2(x3)^22\]
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
Set equal to 0, and get \[2(x3)^22=0\implies(x3)^2=1\]Take the root, and solve. \[x3=\pm1\implies x=4\quad\text{or}\quad x=2\]
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
ok george you are right now can you explain each step
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
The hardest part is the first couple steps. You start with \[2x^212x+16=2(x^26x+8)\]The next part is where you complete the square. You take half of \(6\), square it, and then add/subtract it. So you get\[2(x^26x+8)=2(x^26x+\left(\frac{6}{2}\right)^2\left(\frac{6}{2}\right)^2+8=2(x^26x+99+8)\]
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
Now you simplify as I described before. It's important that you simplify \[x^26x+99+8\]as \((x3)^21\). That's the whole point of completing the square. You add/subtract just the right amount so you can have the square of a binomial. From there, you can solve for that square easily, and then just take a square root.
 2 years ago

KingGeorge Group TitleBest ResponseYou've already chosen the best response.1
Did this make sense?
 2 years ago

countonme123 Group TitleBest ResponseYou've already chosen the best response.1
yes thank you but please view my next question
 2 years ago
See more questions >>>
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.