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If the equation x^2+(7+a)x+7a+1=0 has equal roots,find the value of a.
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ANSWER = {9,5}
 one year ago
 one year ago
If the equation x^2+(7+a)x+7a+1=0 has equal roots,find the value of a. . . . ANSWER = {9,5}
 one year ago
 one year ago

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koli123ableBest ResponseYou've already chosen the best response.0
how should i start
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
For a root with multiplicity two you need to need to have the discriminant equal to 0.
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
So what I'm saying is: \[Ax^2+Bx+C=0 => \text{ discriminant } = B^24AC\] And we want here for the discriminant=0
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
but what is b and a and c the equation is a bit confusing
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
Since we want root with multiplicity 2 :) So \[B^24AC=0\]
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
\[\text{ you have } x^2+(7+a)x+(7a+1)=0\]
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
A is the number in front of x^2 B is the number in front of x C is the leftover part
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
\[x^2+(7+a)x+7a+1=0\]
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
A=1 B=(7+a) c=(7a+1)
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
\[(7+a)^24(1)(7a+1)=0\]
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
That is B^24AC=0 You think you can solve that reply above for a?
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
49+14a+a^214a+4=0
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
I think you mean 28a since 4(7)=28 not 14
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
well .... I think your 53 is a little off. you have 494 you forgot to distribute that  earlier
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
\[49+14a+a^24(7a+1)=0\] \[49+14a+a^228a4=0\] Now try combining like terms.
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
yep do you know how to factor?
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
yep but i am solving this with quadratic is it ok?
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
The quadratic formula? That is fine. :)
 one year ago

MiyuruBest ResponseYou've already chosen the best response.0
I solved it by factors..
 one year ago

MiyuruBest ResponseYou've already chosen the best response.0
thnx @myininaya U are great. Nice help
 one year ago

koli123ableBest ResponseYou've already chosen the best response.0
got 2 values 9 and 5 of a
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
Great! You go guys! :)
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
If you guys didn't understand why I set the discriminant equal to 0, then I will try to explain as best as possible. If discriminant is equal to 0, then you will have on root (multiplicity 2) If discriminant is equal to negative number, you have two imaginary solutions If discriminant is equal to positive number, you have two real solutions.
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
The discriminant is \[B^24AC \]
 one year ago

MiyuruBest ResponseYou've already chosen the best response.0
@myininaya how to solve the equation to get the discriminant..
 one year ago

myininayaBest ResponseYou've already chosen the best response.2
\[x=\frac{b \pm \sqrt{b^24ac}}{2a} \text{ is called the quadratic formual } \] The discriminant is that thing under the radical It is what determines if you have one root (w/ multiplicity 2) , imaginary roots, or real roots.
 one year ago

MiyuruBest ResponseYou've already chosen the best response.0
So to slove the equation should i find a b c
 one year ago
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