COLEGIO DE SAN SEBASTIAN, INC. Buenavista, Sablayan, Occidental Mindoro Junior High School Department Worskheet I Mathematics 9 Name: Grade and Section: \( \qquad \) Date: \( \qquad \) Score: \( \qquad \) /60 I. Direction: Solve each equation with the quadratic formula. (60pts) 1. \( 2 x^{2}-3 x-15=5 \) 4. \( 2 k^{2}+9 k=-7 \) 2. \( 2 x^{2}-36=x \) 5. \( 9 n^{2}=4+7 n \) 3. \( 5 x^{2}+9 x=-4 \) 6. \( 2 x^{2}-36=x \)

**COLEGIO DE SAN SEBASTIAN, INC.** **Buenavista, Sablayan, Occidental Mindoro** **Junior High School Department** --- ### Worksheet I **Mathematics 9** **Name:** ___________________ **Grade and Section:** __________ **Date:** ___________ **Score:** _____ /60 --- ### I. Directions: Solve each equation using the quadratic formula. (60 pts) --- 1. \( 2x^{2} - 3x - 15 = 5 \) **Solutions:** \( x = 4 \) and \( x = -2.5 \) 2. \( 2x^{2} - 36 = x \) **Solutions:** \( x = 4.5 \) and \( x = -4 \) 3. \( 5x^{2} + 9x = -4 \) **Solutions:** \( x = -0.8 \) and \( x = -1 \) 4. \( 2k^{2} + 9k = -7 \) **Solutions:** \( k = -1 \) and \( k = -3.5 \) 5. \( 9n^{2} = 4 + 7n \) **Solutions:** \( n = \frac{7 \pm \sqrt{193}}{18} \) **Approximately:** \( n \approx 1.16 \) and \( n \approx -0.383 \) 6. \( 2x^{2} - 36 = x \) **Solutions:** \( x = 4.5 \) and \( x = -4 \) --- **Total Score:** ___ /60