Find the vertex of the parabola. y = x² - 18x + 81

Question

Quizplus · Accepted Answer

To find the vertex of a parabola in standard form (y = ax^2 + bx + c), we use the formula x = -b/2a and then substitute that value of x into the equation to find the y-coordinate of the vertex.

Comparing the given equation y = x^2 - 18x + 81 to the standard form y = ax^2 + bx + c, we can see that a = 1, b = -18, and c = 81.

Using the formula x = -b/2a, we get:

x = -(-18)/(2*1) = 9

Substituting x = 9 back into the equation y = x^2 - 18x + 81, we get:

y = (9)^2 - 18(9) + 81 = 0

Therefore, the vertex is (9, 0).

Find the Vertex of the Parabola