Пусть log₃x=y
у²-у-2=0
<span><span>D=<span><span>b²</span>−<span><span>4a</span>c</span></span></span>=</span><span><span><span><span><span>(<span>−1</span>)</span>²</span>−<span><span>4·1</span>·<span>(<span>−2</span>)</span></span></span>=<span>1+8</span></span>=<span>9
</span></span><span>у₁=2</span>
<span>у₂=<span>−<span>1
учитывая подстановку у=</span></span></span><span><span>log₃x </span>
2=log₃x
x₁=3²
x₁=9
х₂=3⁻¹
x₂=1/3
</span>
76 см или 7 дм 6 см. ВСЁ просто!!!
D²=((5√3)²+(5√3)²)=(75+75)=150
D²=d²+(5√3)²=150+75=225
D=√225=15