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[tex] 1. \: \frac{(x + 5)(x - 5)}{(x - 5)(x + 3)} = \frac{x + 5}{x + 3} = \frac{10}{8} = \frac{5}{4} [/tex]
[tex]2. \: s = \frac{27}{1 - \frac{1}{3} } = \frac{27}{ \frac{2}{3} } = \frac{81}{2} [/tex]
[tex]3. \: - \frac{1}{3} {x}^{3} - \frac{1}{2} {x}^{2} + 2x = - \frac{3}{2} [/tex]
[tex]x = \frac{3y + 2}{5y - 7} \\ 5xy - 7x = 3y + 2 \\ 5xy - 3y = 7x + 2 \\ y(5x - 3) = 7x + 2 \\ y = \frac{7x + 2}{5x - 3} \\ f(2) = \frac{16}{7} [/tex]