Solve \( -\frac{1}{6}\left[3-15\left(\frac{1}{3}\right)^{2}\right] \)

\( \begin{array}{ll}\text { 1. } 3 x=2 x+18 & \text { 2. } \\ \text { 4. } 4 z+3=6+2 z & \text { 5. } \\ \text { 7. } x=\frac{4}{5}(x+10) & \text { 8. }\end{array} \)

(3) If the point \( (x-5,7-x) \) lies in the second quadrant, then \( x=- \) \( \begin{array}{lll}\text { (a) } 9 & \text { (b) } 3 & \text { (c) } 7\end{array} \)

100. यदि \( 5^{\sqrt[3]{x}}+12^{\sqrt[3]{x}}=13^{\sqrt[3]{x}} \) है, तो \( x \) का मान है: If \( 5^{\sqrt[3]{x}}+12^{\sqrt[3]{x}}=13^{\sqrt[3]{x}} \), then the value of \( x \) is:

VII. Find the solution(s) of the following system. \[ \left\{\begin{array}{r}x_{1}+x_{2}+x_{3}+x_{4}=0 \\ 2 x_{1}+2 x_{2}+3 x_{3}+4 x_{4}=0 \\ 2 x_{1}+2 x_{2}+2 x_{3}+2 x_{4}=0 \\ 3 x_{1}+3 x_{2}+4 x_{3}+5 x_{4}=0\end{array}\right. \]

Solve the exponential equation: \( 3^{2x} = 81 \)