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calculați 2(3 la puterea x+2   +2 ori 3 la puterea x+1 minus 3 laputera x) minus 7=77


Răspuns :

2(3 ˣ⁺² +2 x3ˣ⁺¹ -3 ˣ) - 7=77
2(3 ˣ⁺² +2 x3ˣ⁺¹ -3 ˣ)=77+7
2(3 ˣ⁺² +2 x3ˣ⁺¹ -3 ˣ)=84
3 ˣ⁺² +2 x3ˣ⁺¹ -3 ˣ=84:2
3 ˣ⁺² +2 x3ˣ⁺¹ -3 ˣ=42
3ˣx3²+2x3ˣx3-3ˣ=42
3ˣ(9+6-1)=42
3ˣx14=42
3ˣ=42:14
3ˣ=3
x=1