[tex] 2^{x} = 2^{4} [/tex]⇔x=4
[tex] 3^{x-1} =3^{2} [/tex]⇔x-1=2⇔x=3
[tex] 5^{2x-3} = 5^{3} [/tex]
2x-3=3⇒2x=6⇒x=3
Cn²[tex] \frac{n!}{2!(n-2)!} = \frac{n(n-1)(n-2)!}{2(n-2)!} = \frac{n(n-1)}{2} =6[/tex]=
n(n-1)=12
n²-n-12=0⇒n=4, n=-3 convine doar solutia n=4 ∈N
log₅(2x+1)=2
log₅(2x+1)=log₅25⇔2x+1=25⇒2x=24, x=12