Equation?

[Stefany]

Could someone explain to me how you get the last row. I don’t understand why 11 turns to +11. If the signs are changing why didn’t 28 become -28?
Or did I just get the whole thing wrong?

 

[lev888]

Could someone explain to me how you get the last row. I don’t understand why 11 turns to +11. If the signs are changing why didn’t 28 become -28?
Or did I just get the whole thing wrong?

Please post the complete question.

 

[Dr.Peterson]

Could someone explain to me how you get the last row. I don’t understand why 11 turns to +11. If the signs are changing why didn’t 28 become -28?
Or did I just get the whole thing wrong?

If x₁ and x₂ are given as the roots of the equation, then the middle term is not their sum, but the negative of their sum.

In addition to showing the complete problem statement, please show us what you were taught that justifies what you did -- a theorem or formula or something like that. It may be something like these:

Vieta's formulas - Wikipedia

en.wikipedia.org

Polynomials: Sums and Products of Roots

www.mathsisfun.com

 

[Stefany]

Please post the complete question.

The first part is the question and the second part is suppose to be the solution.

I think you’re suppose to create an equation using only x1 and x2.

 

[Stefany]

If x₁ and x₂ are given as the roots of the equation, then the middle term is not their sum, but the negative of their sum.

In addition to showing the complete problem statement, please show us what you were taught that justifies what you did -- a theorem or formula or something like that. It may be something like these:

Vieta's formulas - Wikipedia

en.wikipedia.org

Polynomials: Sums and Products of Roots

www.mathsisfun.com

I wasn’t really given a formula, just the solution and a couple of other examples. That’s why I’m confused. I have the solution but I don’t understand it...

 

[Dr.Peterson]

The first part is the question and the second part is suppose to be the solution.

I think you’re suppose to create an equation using only x1 and x2.

No, something has to have been said about what x₁ and x₂ are, or it is meaningless! Can't you show us the actual problem? Even if it's in another language, it can help.

I wasn’t really given a formula, just the solution and a couple of other examples. That’s why I’m confused. I have the solution but I don’t understand it...

Please just tell us what you were taught, whether it is called a formula or not. If it was only examples, show us the examples, so we can see if you are extrapolating incorrectly from them. We need to see on what grounds you think what you did should be right, so we can correct that.

 

[lev888]

The first part is the question and the second part is suppose to be the solution.

I think you’re suppose to create an equation using only x1 and x2.

If you don't know what's going on, say so. The first part is NOT a question if the only thing there is 2 variables and their values.

 

[Stefany]

If you don't know what's going on, say so. The first part is NOT a question if the only thing there is 2 variables and their values.

Ok, then I don’t know what’s going on.

 

[Stefany]

No, something has to have been said about what x₁ and x₂ are, or it is meaningless! Can't you show us the actual problem? Even if it's in another language, it can help.


Please just tell us what you were taught, whether it is called a formula or not. If it was only examples, show us the examples, so we can see if you are extrapolating incorrectly from them. We need to see on what grounds you think what you did should be right, so we can correct that.

X1 and X2 for the roots of the equation. With them you have to make a quadratic equation using Viet's formulas.
That’s what I found out, if that helps

 

[lev888]

Ok, then I don’t know what’s going on.

Assuming the 2 values are the roots and you need to produce the corresponding quadratic equation, take a look here:

Formation of Quadratic Equation with Given Roots

Formation of Quadratic Equation with Given Roots

www.onlinemath4all.com

Or you can just write the equation in factored form, then multiply and simplify:
(x-x1)(x-x2)=0

 

[Stefany]

Assuming the 2 values are the roots and you need to produce the corresponding quadratic equation, take a look here:

Formation of Quadratic Equation with Given Roots

Formation of Quadratic Equation with Given Roots

www.onlinemath4all.com

Or you can just write the equation in factored form, then multiply and simplify:
(x-x1)(x-x2)=0

Thanks

 

[Dr.Peterson]

X1 and X2 for the roots of the equation. With them you have to make a quadratic equation using Viet's formulas.
That’s what I found out, if that helps

If that is what the question really says, and what you were taught, then the links lev888 and I showed you are appropriate. I do wish you would show what we ask for rather than hide facts.

On the other hand, what I would do is just to write the factored form (x - 7)(x - 4)=0 and expand, as lev888 said. That seems a lot easier to me, and harder to forget.

 

[Steven G]

You wrote that x1=7 and x2=4, but on the lines that followed you replace x1 with -7? That is a big mistake. Something is wrong with the problem you gave us. This is why you have been asked repeatedly to show the original problem.