4. Write an equation to represent the relationship between the number of times Carlo goes to the gym and the cost of his membership using the "Pay As You Go" option.' 5. After 10 months of having the "Pay As You Go" membership, Carlo had visited the gym 30 times. How much money had he paid? Justify your answer by showing your mathematics.

3. Mathon went to Inkhorn Bookstore where he got a discount of P15 from a book that was marked \( 20 \% \) off. Then, he went to Lofty Bookstore to check out one of their limited edition books that is now discounted at \( 30 \% \). If Mathon got a discount on the book from the Lofty Bookstore for the same amount as the original price of the book he got from Inkhorn Bookstore, how much is the difference between the two books' original prices?

Solve for \( x \) by completing the square: \( x^{2}=-3 x+10 \)

Solve for \( x \) if \( x=\sqrt{x+\sqrt{x+\sqrt{x+\sqrt{x+\sqrt{x+\ldots}}}}} \)

\begin{tabular}{l} 25. \begin{tabular}{l}\( -6 x+4 y \geq 8 \) \\ \( y<-x-1 \) \\ \begin{tabular}{|l|l|l|l|}\hline \\ \hline & \\ \hline\end{tabular} \\ \hline \\ \hline\end{tabular} \\ \hline\end{tabular}

¿Cuál de las siguientes expresiones es igual a \( (2 x-3)^{2} ? \) A) \( 2 x^{2}-12 x+9 \) B) \( 4 x^{2}-6 x-9 \) C) \( 4 x^{2}-12 x+9 \) D) \( 4 x^{2}-9 \)