Given the quadratic function y = - x ^ 2-8x + 3, when - 7 ≤ x ≤ - 3, if x =, the function has the maximum value, if x =, the function has the minimum value

Given the quadratic function y = - x ^ 2-8x + 3, when - 7 ≤ x ≤ - 3, if x =, the function has the maximum value, if x =, the function has the minimum value

y=-x^2-8x+3,
=-(x+4)^2+3+16
=-(x+4)^2+19
If x = - 4, the function has a maximum of 19
If x = - 7, the function has a minimum value of 10

Given the quadratic function y = (3-K) x2 + 2, find: (1) when what is the value of K, the function has the maximum value? What is the maximum value? (2) When k is what value, the function has the minimum value? What is the minimum value?

(1) When 3-K ＜ 0, i.e. K ＞ 3, the function has a maximum value of 2; (2) when 3-K ＞ 0, i.e. K ＜ 3, the function has a maximum value of 2

What are the minimum and maximum values of the quadratic function y = (x-4) (x + 2)
We need the process, otherwise we won't adopt it
In this paper, we discuss the formula (method) for solving the maximum and minimum of quadratic function y = (x-x1) (x-x2)
thank you

y=(x-4)(x+2)
=x^2-2x-8
=(x-1)^2-9
When x = 1
ymin=-9
There is no maximum value for quadratic function opening upward
y=(x-x1)(x-x2)
When x = (x1 + x2) / 2
Y to the minimum
There is also no maximum