Question

What is the vertex of the graph of the function below?

y=x²-4x+3
O A. (1,-1)
OB. (2,-1)
O C. (2,0)
O D. (1.0)

Answer 1

B

Explanation:

given a quadratic function in standard form

y = ax² + bx + c ( a ≠ 0 ) , then the x- coordinate of the vertex is

x = -
`(b)/(2a)`

y = x² - 4x + 3 ← is in standard form

with a = 1, b = - 4 , then

x = -
`(-4)/(2)` = 2

substitute into the equation for corresponding y- coordinate

y = 2² - 4(2) + 3 = 4 - 8 + 3 = - 1

vertex = (2, - 1 )