Question

Complete the square to determine the maximum or minimum value of the function defined by the expression. x2 − 6x + 5 A) minimum value at 5 B) maximum value at 4 C) minimum value at −4 D) maximum value at −5

Answer 1

$y=ax^2+bx+c\to y=x^2-6x+5$

a = 1 > 0 therefore, this function has minimum.

Use $(*)\ (a-b)^2=a^2-2ab+b^2$

$x^2-6x+5=x^2-2\cdot x\cdot3+5=\underbrace{x^2-2\cdot x\cdot3+3^2}_{(*)}-3^2+5\\\\=(x-3)^2-9+5=(x-3)^2-4$

Answer: C) minimum value at −4.

Answer 2

Answer: C

Step-by-step explanation: trust me it's right