Question

What is the axis of symmetry and vertex given the equation,
y=2x^2-12x+21

Answer 1

Answer: 2(x + 3)² + 3

Explanation: Axis of symmetry: x = -3 Vertex: (-3, 3)

Answer 2

y = 2x² - 12x + 21 = 2(x² + 6x) + 21.

Using the complet the square method, you get:

2(x² + 6x) + 21 = 2(x² + 6x + 9) - 2*9 + 21 = 2(x + 3)² + 3.

So the axis of symmetry is: x = -3.

The vertex is: (-3, 3)