4x mũ 2 -9=0 25x mũ 2 -9=0 16x mũ 2 -8x +1=o hãy tìm x

1.4x^2-9=0

4x^2 =9

x^2 =9/4

x^2 =(3/2)^2

x =3/2

2.25x^2-9=0

25x^2 =9

x^2 =9/25

x^2 =(3/5)^2

x =3/5

3.16x^2-8x+1 =0

4^2x^2-8x+1=0

(4x-1)^2 =0

4x-1 =0

4x =1

x =1/4