Answer:
maximum value y = 30
Explanation:
Given
- x² + 10x + 5
To complete the square the coefficient of the x² term must be 1
factor out - 1
= - (x² - 10x) + 5
To complete the square
add/subtract ( half the coefficient of the x- term )² to x² - 10x
= - (x² + 2(- 5)x + 25 - 25) + 5
= - (x - 5)² + 25 + 5
= - (x - 5)² + 30 ← in vertex form
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Hence vertex = (5, 30)
The max/ min occurs at the vertex
Since a < 0 then vertex is a maximum
Hence maximum value is y = 30