Question

Find the vertex of the parabola whose equation is y = x^2 - 4x + 6.

A. (-2, 18)
B. (2, 2)
C. (2, 6)

Answer 1

B. (2,2).

Explanation:

Convert to vertex form y = a(x - b)^2 + c where (b, c) is the vertex.

y =x^2 - 4x + 6

y = (x - 2)^2 - 4 +6

y = (x - 2)^2 + 2.

Therefore the vertex is (2, 2).

Answer 2

`\bf \textit{vertex of a vertical parabola, using coefficients} \\\\ y=\stackrel{\stackrel{a}{\downarrow }}{1}x^2\stackrel{\stackrel{b}{\downarrow }}{-4}x\stackrel{\stackrel{c}{\downarrow }}{+6} \qquad \qquad \left(-\cfrac{ b}{2 a}~~~~ ,~~~~ c-\cfrac{ b^2}{4 a}\right) \\\\\\ \left(-\cfrac{-4}{2(1)}~~,~~6-\cfrac{(-4)^2}{4(1)} \right)\implies (2~~,~~6-4)\implies (2~,~2)`