Which equation has roots of -3 and 5

Which equation has roots of -3 and 5

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BRUCE S. | Learn & Master Physics & Math with Bruce SLearn & Master Physics & Math with Bruce...

Sherry,

This is like 'Algebra Jeopardy'....Given the answer, what is the question!?

For a quadratic equation like x^2 + b*x + c =0 you end up with factoring usually like this:

(x+w)(x+z)=0

The the roots are x = -w, -z

The problem gives the roots -w and -z so now just subsitute:

-w = -3 and -z = 5

The factored equation is:

(x+3)(x-5) = 0 or expanded it is:

X^2 +3*x -5*x -15 = 0

Note: I have assumed a quadratic equation but there are many equaitons of other types with these roots. For example:

x+3 =0 so x=-3

x-5 = 0 so x=5

(x+3)(x+3)(x-5) = 0 This is a third order polynomial with a double root: x=-3

And so it goes...

*BruceS*

Grigori S. | Certified Physics and Math Teacher G.S.Certified Physics and Math Teacher G.S.

Ben H. | Ben the Awesome TutorBen the Awesome Tutor

If the roots are -3 and 5

Then the formula is

(x-3)(x+5)=0

or

**x ^{2}+2x-15=0**

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## Comments

This is backwad as shown by Bruce below. It should be:

(X+3) (X-5) = 0

Because X+3 = 0 is solved as X = -3 and X - 5 = 0 is solved as X = 5