Read the following description of a relationship: Tori uses 12 tomatoes to make each bowl of salad. Let \( s \) represent the number of bowls of salad and \( t \) represent the total number of tomatoes she uses. Use the function \( t=12 s \) to find the value of \( t \) when \( s=7 \).

Solve for \( x \) and \( y \) simultaneously: \( 3^{x+y}=27 \quad \) and \( \quad x^{2}+y^{2}=17 \)

The ratio between the sum of the fifth, sixth and seventh terms of a geometric series and the sum of the first three terms of the same series is \( 81: 16 \). Determine the sum of the first ten terms, if the first term is 1024 .

76. Решите графически систему линейных уравнений: \( \begin{array}{ll}\text { а) }\left\{\begin{array}{l}x-y=1, \\ x+3 y=9 ;\end{array}\right. & \text { в) }\left\{\begin{array}{l}x+y=0, \\ -3 x+4 y=14 ;\end{array}\right. \\ \text { б) }\left\{\begin{array}{ll}x+2 y=4, \\ -2 x+5 y=10 ; & \text { г) }\left\{\begin{array}{l}3 x-2 y=6, \\ 3 x+10 y=-12\end{array}\right.\end{array}\right.\end{array} \).

7. Show that the set F of the six complex valued functions: \( f_{1}(z)=z, f_{2}(z)=\frac{1}{1-z}, f_{3}(z)=\frac{z-1}{z} \) \( f_{4}(z)=\frac{1}{z}, f_{5}(z)=1-z, f_{6}(z)=\frac{z}{z-1} \) is a group under the usual multiplication of mappings.

\( 6 x^{3}-5 x^{7}+6 \) leading term? Leading cafficient? Turning Caint?