The sum of 8 term of an A.P is 160 while the sum 20 term is 880-Find; (a) 43 rd term Sum of 12 terms

\( \frac{2}{3}\left(\frac{3}{5}-\frac{3}{4}\right)+\frac{1}{2} \div \frac{1}{4} \) Step \( 1 \div \frac{2}{3}\left(-\frac{3}{20}\right)+\frac{1}{2} \div \frac{1}{4} \) Step \( 2:-\frac{1}{10}+\frac{1}{2} \div \frac{1}{4} \) Step \( 3:-\frac{1}{10}+\frac{1}{8} \) Step \( 4: \frac{1}{40} \)

2. (20 points) Solve the system of linear equations using the Gaussian elimination method (or the Gauss-Jordant \[ \left\{\begin{array}{l}x_{1}+x_{2}+2 x_{3}=3 \\ 2 x_{1}+3 x_{2}+2 x_{3}=8 \\ -x_{1}+2 x_{2}-7 x_{3}=4\end{array}\right. \]

Simplify: \( \frac{25-25 y^{2}}{3 y^{2}-3} \div \frac{9 y^{2}-6 y+1}{3 y^{2}-3} \times \frac{(3 y-1)^{2}}{-5 y^{3}+5 y} \)

Math on the Spot Sophia uses \( 3 \frac{3}{4} \) cups-bf flour for each cake she makes. She has a 10 -pound bag of flour that cost \( \$ 8.79 \) and contains 152 quarter-cup servings. A. How many cakes can Sophia make with this flour? B. Use your answer from Part A to find the cost of the flour for each cake Round your answer to the nearest cent.

2. (UECE) Se ié ó número complexo cujo quadrado é igual \( a-1 \), entáo, o valor de \( 5 \cdot i^{227}+i^{6}-i^{13} \) é igual a \( \begin{array}{ll}\text { a) } i+1 & \text { c) }-6 i-1 \\ \text { b) } 4 i-1 & \text { d) }-6 i\end{array} \)