SOLUTION: If i have roots or solution m and n, what can i do to identify the standard form of the given roots?

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: If i have roots or solution m and n, what can i do to identify the standard form of the given roots?       Log On


   



Question 890611: If i have roots or solution m and n, what can i do to identify the standard form of the given roots?

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
IN GENERAL:
A quadratic equation is an equation of degree 2 , so you know that there will be an x%5E2 somewhere.
If you know that m and n are solutions (or roots) of a quadratic equation,
you can write a quadratic equation with those solutions as
%28x-m%29%28x-n%29=0 .
That is the equation in factored form.
If you multiply the factors %28x-m%29 and %28x-n%29 and simplify the result,
you get a more elegant quadratic equation that your teacher will like better.
There are infinite quadratic equations with those roots (or solutions).
You can transform a quadratic equation into an equivalent one
(one with exactly the same solutions, no more or less solutions, no different solutions)
by multiplying both sides of the equation by a number other than zero:
Take any a%3C%3E0 , and
%28x-m%29%28x-n%29=0 ---> a%2A%28x-m%29%28x-n%29=a%2A0 ---> a%28x-m%29%28x-n%29=0
(If you multiplied both sides times zero you would end up with 0=0 that is not much of an equation).

EXAMPLE:
For example, if the solutions or roots of a quadratic equation are -3 and 1%2F2 , I would write
%28x-%28-3%29%29%28x-1%2F2%29=0 ---> %28x%2B3%29%28x-1%2F2%29=0 ---> x%5E2-%281%2F2%29x%2B3x-3%2F2=0 ---> x%5E2%2B%285%2F2%29x-3%2F2=0 ---> 2%2A%28x%5E2%2B%285%2F2%29x-3%2F2%29=2%2A0 ---> highlight%282x%5E2%2B5x-3=0%29
All those equations are equivalent, but the last one is the simplest and most elegant of them.
I could multiply both sides times a non-zero number, let's say 100 , to get an elegant but unnecessarily complicated equation:
200x%5E2%2B500x-300=0 .

EXTRA:
Also, with the same roots I can write equations of a degree higher than 2 (not quadratic),
by multiplying both sides times some polynomial, like x or %28x%5E2%2B1%29 .