Question

Найдите наибольшее значение функции y=-2x^2-8x+5 Пожалуйста!! Срочно!!

Answer 1

Так как вы пишите, что у вас 5-9 класс, то решение такое.
Парабола $y=-2x^2-8x+5$ направлена ветвями вниз, т.к. -2<0. Значит наибольшее значение будет в вершине. Найдём координаты вершины.

$x_{versh}=-\frac{b}{2a}=-\frac{-8}{-4}=-2\\\\y_{versh}=-2\cdot (-2)^2-8\cdot (-2)+5=13\\\\y_{naibolshee}=13$

Answer 2

Finding the Maximum Value of the Function y = -2x^2 - 8x + 5

To find the maximum value of the function y = -2x^2 - 8x + 5, we can use the formula for the vertex of a parabola, which is given by x = -b/2a. Once we find the x-coordinate of the vertex, we can substitute it into the original function to find the corresponding y-coordinate.

The formula for the x-coordinate of the vertex of a parabola in the form y = ax^2 + bx + c is x = -b/2a.

In the given function y = -2x^2 - 8x + 5, we have: - a = -2 - b = -8

Plugging these values into the formula, we get: x = -(-8)/(2*(-2)) = 8/(-4) = -2

Now that we have the x-coordinate of the vertex, we can find the corresponding y-coordinate by substituting x = -2 into the original function y = -2x^2 - 8x + 5.

Substituting x = -2 into the function, we get: y = -2(-2)^2 - 8(-2) + 5 = -2*4 + 16 + 5 = -8 + 16 + 5 = 13

So, the maximum value of the function y = -2x^2 - 8x + 5 is y = 13.