What is the axis of symmetry of the parabola...?
回答 (4)
Take the general form of the parabola:
y = ax² + bx + c
The line of symmetry is:
x = -b/(2a)
If you need help remembering that, it's the same as the quadratic formula but without the ±√ part.
In your case:
a = 1
b = -4
x = -(-4) / (2*1)
x = 4/2
x = 2
Answer:
C. x = 2
Complete the square.
y = x^2 - 4x - 5
y = x^2 - 4x + 4 - 9
y = (x - 2)^2 - 9
axis of symmetry is x = 2
What is the axis of symmetry of the parabola y = x^2 - 4x - 5?
y = (x - 5)(x + 1)
C x = 2
Do you want the short answer or the long answer.
Short answer
Graph it and look for yourself
x = 2
long answer
take derivative
f'(x) = 2 x - 4
set to 0 and solve for x
0 = 2x - 4
4 = 2x
2 = x
收錄日期: 2021-05-01 22:11:54
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20201001191144AAikfSF
檢視 Wayback Machine 備份