Inter. Algebra: Complete square for 12d^2 + 23d + 10 = 0

[Helen]

Solve the equation by completing the square.
This is the problem: 12d^(2) + 23d + 10 = 0
My answer: [ 3/2, 4/5}
I believe this answer is correct, I would just like another opinion.

 

[o_O]

Re: Intermediate Algebra

Did you try plugging it back into the equation? What do you get if you plug them in? Also, show us your work for getting the actual solutions so we can point out any errors.

 

[Helen]

Re: Intermediate Algebra

, Thank you, I will recheck my work. Helen

 

[stapel]

I believe this answer is correct....

It has been explained to you, in many of your other recent threads, how to check if the solution to an equation is correct. So you know quite well how to do that part.

This suggests that you are actually asking us to check your completing-the-square process. Unfortunately, you did not show your work, which makes it impossible for us to check your steps or methodology. Sorry.

Eliz.

 

[Helen]

Liz,
I understand, thank you for the advice. Helen

 

[PAULK]

Solve the equation by completing the square.
This is the problem: 12d^(2) + 23d + 10 = 0
My answer: [ 3/2, 4/5}
I believe this answer is correct, I would just like another opinion.

................................................................
There are other ways to check solutions to a quadratic, besides brute force substitution:

The sum of the roots is -b/a.
The product is c/a.

In your example, a = 12, b = 23, c = 10

The sum is -b/a = -23/12

Your two positive roots cannot add up to -23/12, so I believe they are wrong. (you wanted another opinion, right?)

 

[galactus]

Your solutions of 4/5 and 3/2 are the negative reciprocals of the correct solutions.

Completing the square for said function:

\(\displaystyle 12(x+\frac{23}{24})^{2}-\frac{49}{48}=0\)

 

[Helen]

Galactus and Paulk, Thank you for your help. Helen