Question 132855
Find a quadratic equation of the form ax^2+bx+c=0 whose solutons are 
{{{x=4+-sqrt(11)}}}
<pre><font size = 4><b>

Formula:

A quadratic equation of the form {{{ax^2+bx+c=0}}} which has solutions M and N
is {{{x^2-(M+N)x+MN=0}}}

Therefore:

{{{M = 4+sqrt(11)}}}, {{{N = 4-sqrt(11)}}}

{{{M+N=4+sqrt(11)+4-sqrt(11)}}} = {{{8}}}

{{{MN=(4+sqrt(11))(4-sqrt(11))}}} = {{{16-4sqrt(11)+4sqrt(11)-sqrt(11)sqrt(11)}}} = {{{16-cross(4sqrt(11))+cross(4sqrt(11))-11}}} = {{{16-11}}} = {{{5}}}.

So substituting in 

{{{x^2-(M+N)x+MN=0}}} 

gives the equation

 {{{x^2-8x+5=0}}}

Edwin</pre>