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| Question 1209271:  Find the vertex of the graph of the equation y = -2x^2 + 8x - 15 - 5x^2 + 17x + 20.
 Answer by asinus(45)
      (Show Source): 
You can put this solution on YOUR website! **1. Combine Like Terms** * y = -2x² + 8x - 15 - 5x² + 17x + 20
 * y = -7x² + 25x + 5
 **2. Find the Vertex**
 * **Vertex Formula:** For a parabola in the form y = ax² + bx + c, the vertex is given by:
 * x-coordinate of the vertex: x = -b / 2a
 * **In this case:**
 * a = -7
 * b = 25
 * x = -25 / (2 * -7) = 25/14
 * **Find the y-coordinate of the vertex:**
 * Substitute the x-coordinate of the vertex back into the equation:
 * y = -7(25/14)² + 25(25/14) + 5
 * y = -7(625/196) + 625/14 + 5
 * y = -225/28 + 625/14 + 5
 * y = 225/7 + 5
 * y = 265/7
 **Therefore, the vertex of the graph is (25/14, 265/7).**
 
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