Question

rezolva in multimea numerelor intregi ecuatiile:a)x la 2=16
b) 5x la 2 =180
c) x la 2 =729
d) 4 supra x = x supra 9

Answer 1

$\frac{4}{x} = \frac{x}{9} =\ \textgreater \ x * x = 4 * 9 =\ \textgreater \ x^{2} = 36$a) x² = 16 
Cum x ∈ Z ⇒ ║x║ (modul de x) = 4
1. x = -4
2. x = 4

b) 5x² = 180
x² = 36
x ∈ Z ⇒ ║x║= 6 ⇒ x = 6 ; -6

c) x² = 729
x ∈ Z ⇒ ║x║= 27 ⇒ x = 27 ; -27

d) $\frac{4}{x} = \frac{x}{9} =\ \textgreater \ x * x = 4 * 9 =\ \textgreater \ x^{2} = 36$ 
x ∈ Z ⇒ x = 6 ; -6