SOLUTION: how do i write a quadratic expression from the answer, the answer being; - sqrt(5), 6 sqrt(5) ?? please demonstrate so i can learn this.

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: how do i write a quadratic expression from the answer, the answer being; - sqrt(5), 6 sqrt(5) ?? please demonstrate so i can learn this.      Log On


   

Question 376338: how do i write a quadratic expression from the answer, the answer being; - sqrt(5), 6 sqrt(5) ??
please demonstrate so i can learn this.
Found 2 solutions by jim_thompson5910, edjones:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Recall that if p and q are solutions, then x=p or x=q


So in this case, this means that if sqrt%285%29 or 6%2Asqrt%285%29 are solutions then x=sqrt%285%29 or x=6%2Asqrt%285%29


x=sqrt%285%29 or x=6%2Asqrt%285%29 Start with the given solutions.


x-sqrt%285%29=0 or x-6%2Asqrt%285%29=0 Get everything to the left side.


%28x-sqrt%285%29%29%28x-6%2Asqrt%285%29%29=0 Use the zero product property


x%5E2-6%2Asqrt%285%29%2Ax-sqrt%285%29%2Ax-sqrt%285%29%28-6%2Asqrt%285%29%29=0 FOIL


x%5E2-7%2Asqrt%285%29%2Ax%2B30=0 Multiply and combine like terms.


So the quadratic expression is x%5E2-7%2Asqrt%285%29%2Ax%2B30


If you need more help, email me at jim_thompson5910@hotmail.com

Also, feel free to check out my tutoring website

Jim

Answer by edjones(8007) About Me  (Show Source):
You can put this solution on YOUR website!
x=-sqrt(5), x=6sqrt(5)
(x+sqrt(5))(x-6sqrt(5))=0
f(x)=x^2-5sqrt(5)x-30 FOIL