The equation of the axis of symmetry of a parabola in the form 𝑦 = 𝑎𝑥2 + 𝑏𝑥 + 𝑐 is given by:
𝑥 = -𝑏/2𝑎
In the given equation, 𝑎=1, 𝑏= -10, and 𝑐=16.
Therefore, the equation of the axis of symmetry is:
𝑥 = -(-10)/2(1) = 5
So, the equation of the axis of symmetry is 𝑥 = 5.
A parabola is defined by the equation 𝑦 = 𝑥2 − 10𝑥 + 16
State the equation of the axis of symmetry
3 answers
or complete the square
𝑦 = 𝑥2 − 10𝑥 + 16
y = x^2 - 10 x - (10/2)^2 + (10/2)^2 + 16
x^2 - 10 x - 25 + 25 + 16
so
y = (x-5) ^2 + 25 + 16
symmetric about vertical line x = 5
by the way the vertex must be on that line so at y = 25+16 = 41
𝑦 = 𝑥2 − 10𝑥 + 16
y = x^2 - 10 x - (10/2)^2 + (10/2)^2 + 16
x^2 - 10 x - 25 + 25 + 16
so
y = (x-5) ^2 + 25 + 16
symmetric about vertical line x = 5
by the way the vertex must be on that line so at y = 25+16 = 41
That's correct! Completing the square is another way to find the axis of symmetry and the vertex of the parabola. In this case, we can rewrite the equation as:
𝑦 = (𝑥2 − 10𝑥 + 25) - 25 + 16
The expression inside the parentheses is a perfect square trinomial:
𝑥2 − 10𝑥 + 25 = (𝑥 − 5)2
So, we can simplify the equation as:
𝑦 = (𝑥 − 5)2 - 9
This shows that the parabola is symmetric about the vertical line 𝑥 = 5, and the vertex is at (5, -9 + 41) = (5, 32).
Great job!
𝑦 = (𝑥2 − 10𝑥 + 25) - 25 + 16
The expression inside the parentheses is a perfect square trinomial:
𝑥2 − 10𝑥 + 25 = (𝑥 − 5)2
So, we can simplify the equation as:
𝑦 = (𝑥 − 5)2 - 9
This shows that the parabola is symmetric about the vertical line 𝑥 = 5, and the vertex is at (5, -9 + 41) = (5, 32).
Great job!