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Determinati nr.nat. care determina relatiile:
c)5*3^x-2*3^x=81
d)3^2x+1-3^2x-3^2x-1-3^2x-2-3^2x-3=123

Răspuns :

Renatemambouko
c)5*3^x-2*3^x=81
3^x *(5-2)=3^4
3^x *3=3^4
3^(x+1)=3^4
x+1=4
x=3

d) 3^(2x+1)-3^2x-3^(2x-1)-3^(2x-2)-3^(2x-3)=123
3^(2x-3)*(3^4-3^3-3^2-3^1-3^0)=123
3^(2x-3)*(81-27-9-3-1)=123
3^(2x-3)*41=123
3^(2x-3)=3
3^(2x-3)=3^1
2x-3=1
2x=4
x=2


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