Дробь 2/5 = 0,4 в десятичных дробях
- 2 + 0,6b - 0,4(3b - 5) = - 2 + 0,6b - 1,2b + 2 = - 0,6b
![16*(log_{9}45-log_{9}9)*log_{11}9*log_{5}11^{2}=16*log_{9} \frac{45}{9}* \frac{1}{log_{9}11}*2log_{5}11=](https://tex.z-dn.net/?f=16%2A%28log_%7B9%7D45-log_%7B9%7D9%29%2Alog_%7B11%7D9%2Alog_%7B5%7D11%5E%7B2%7D%3D16%2Alog_%7B9%7D+%5Cfrac%7B45%7D%7B9%7D%2A+%5Cfrac%7B1%7D%7Blog_%7B9%7D11%7D%2A2log_%7B5%7D11%3D)
![32*\frac{log_{9}5}{log_{9}11}*log_{5}11=32*log_{11}5*log_{5}11=32* \frac{1}{log_{5}11}*log_{5}11=32](https://tex.z-dn.net/?f=32%2A%5Cfrac%7Blog_%7B9%7D5%7D%7Blog_%7B9%7D11%7D%2Alog_%7B5%7D11%3D32%2Alog_%7B11%7D5%2Alog_%7B5%7D11%3D32%2A+%5Cfrac%7B1%7D%7Blog_%7B5%7D11%7D%2Alog_%7B5%7D11%3D32)
<u>Использовались свойства логарифмов:</u>
1)
![log_{a}b-log_{a}c=log_{a}\frac{b}{c}](https://tex.z-dn.net/?f=log_%7Ba%7Db-log_%7Ba%7Dc%3Dlog_%7Ba%7D%5Cfrac%7Bb%7D%7Bc%7D)
2)
![log_{a}b=\frac{log_{c}b}{log_{c}a}=\frac{1}{log_{b}a}](https://tex.z-dn.net/?f=log_%7Ba%7Db%3D%5Cfrac%7Blog_%7Bc%7Db%7D%7Blog_%7Bc%7Da%7D%3D%5Cfrac%7B1%7D%7Blog_%7Bb%7Da%7D)
Х/3=+/-(П-arccos1/2)+2Пn
х/3= +/- 5П/6 + 2Пn
х= +/- 15П/6+ 6Пn
Здесь два уравнения где 1)х=9/9=1; 2) х=90/90=1.