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Explicație pas cu pas:
5ˣ⁺¹⁻¹+5²ˣ⁺²⁻⁽ˣ⁺¹⁾+5³ˣ⁺³⁻⁽²ˣ⁺¹⁾=31, => 5ˣ+5²ˣ⁺²⁻ˣ⁻¹+5³ˣ⁺³⁻²ˣ⁻¹=31, => 5ˣ+5ˣ⁺¹+5ˣ⁺²=31, => 5ˣ·1+5ˣ·5¹+5ˣ·5²=31, => 5ˣ·(1+5+25)=31, => 5ˣ·31=31, => 5ˣ=1 => x=0.
5^(x+1-1)+5^(2x+2-x-1)+5^(3x+3-2x-1)=31
5^x+5^(x+1)+5^(x+2)=31
5^x·(1+5+5²)=31 ⇒ 31·5^x=31 ⇒ 5^x=1 5^x=5^0
x=0
