let's call the solutions xβ = (5 - 2β7)/3 and xβ = (5 + 2β7)/3
then the equation is (x-xβ)(x-xβ) = 0
if you fill that in you get a lot of numbers which you can recognize as axΒ²+bx+c=0.
step-by-step explanation:
you can see that a=1 (there is just an xΒ²)
b = (-5 -2β7 + 2β7 - 5)/3 = -10/3
c = -2β7)/3 ) * (-5+2β7)/3) = -1/3
so your answer is 3x^2 β 10x β 1 = 0