Question

{X∈Q\ 2x2-3X+1=0 } = { 1 supra 2, 1 }

Answer 1

$2 x^{2} -3x+1=0$
Δ=$b^{2}-4ac=9-8=1 \\ x_{1}= \frac{3-1}{4}= \frac{1}{2} \\ x_{2}= \frac{3+1}{4} =1$
x∈{1/2;1}