Răspuns:
Explicație pas cu pas:
a) 4x-9= 0 <=> 4x = 9 => x = 9/4 ∈ Q
b) 25x-175 = 0 <=> 25x = 175 I:25 => x = 7 ∈ Q
c) 3x-√3 = 0 <=> 3x = √3 => x = √3/3 ∉ Q ; nu are solutii in Q
d) 2x+9=0 <=> 2x = -9 => x = -9/2 ∈ Q
e) ⁴⁾4/5 + ⁵⁾3x/4 = ²⁰⁾0 => 16+15x = 0 =>
15x = -16 => x = -16/15 ∈ Q
f) [√(45/16)]·x - √5 /2 = 0 <=>
[√(9·5)/(4·4)]·x = √5 /2 =>
(3√5 /4) ·x = ²⁾√5 /2 =>
(3√5)·x = 2√5 => x = (2√5)/(3√5) => x = 2/3 ∈ Q
