Which equation has roots of -3 and 5
Which equation has roots of -3 and 5
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:
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
If the roots are -3 and 5
Then the formula is
(x-3)(x+5)=0
or
x^{2}+2x-15=0
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