help intercepts

[Guest]

5. Which of these quadratic functions has exactly one x -intercept?
o A. y=x 2 −9
o B. y=x 2 −6x+9
o C. y=x 2 −5x+6
o D. y=x 2 +x−6

A

2. What are the x-intercepts of y=(x−2)(x+5) ?
o A. (0, 2) and (0, -5)
o B. (0, -2) and (0, 5)
o C. (-2, 0) and (5, 0)
o D. (2, 0) and (-5, 0)

D

5. Which of these quadratic functions has exactly one x -intercept?
o A. y=x 2 −9
o B. y=x 2 −6x+9
o C. y=x 2 −5x+6
o D. y=x 2 +x−6

A

2. Which of the following parabolas opens upward and appears narrower than y=−3x 2 +2x−1 ?
o A. y=4x 2 −2x−1
o B. y=−4x 2 +2x−1
o C. y=x 2 +4x
o D. y=−2x 2 +x+3

C


my answers correct or not

thanks

[Baltuilhe]

5)
A. [tex]y=x^2-9=(x+3)(x-3)[/tex]
B. [tex]y=x^2-6x+9=(x-3)^2[/tex]
C. [tex]y=x^2-5x+6=(x-2)(x-3)[/tex]
D. [tex]y=x^2+x-6=(x-2)(x+3)[/tex]

So, the only function is B (intercept in x=3)
Another way is to calc [tex]\Delta[/tex]. If it's zero, only one intercept

2)
Correct!

5)
Repeated?

2)
[tex]y=-3x^2+2x-1[/tex]
To get a narrower 'parabola' you need the quadratic term to be bigger. So:
[tex]y=4x^2-2x-1[/tex]
Has quadratic term equal to 4 and upward. So, narrower than the given one.
A)

I hope I have helped!

[Guest]

thanks much