Final answer:
To find the value of x that minimizes or maximizes y = x² + 10x - 45, use the vertex formula: x = -b/2a. Plugging in the values of a = 1, b = 10, and c = -45, x is found to be -5.
Step-by-step explanation:
To find the value of x that minimizes or maximizes y = x² + 10x - 45, we can use the vertex formula. The vertex formula states that the x-coordinate of the vertex of a quadratic function in the form y = ax² + bx + c is given by x = -b/2a. In this case, a = 1, b = 10, and c = -45. Plugging these values into the formula, we get x = -10/2(1) = -5.