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Quadratic graphs - Quiz 3   Last unanswered question  Question  Next unanswered question

Question 1 lion

Which of the following graphs represent  y = 2- x2?
a) PIC   b) PIC
c) PIC   d) PIC

 

Your answer is correct.
This is  y = 2- x2   since it is concave down and has a  y -intercept of  2 .
Not correct. Choice (b) is false.
Try again, this is the graph of the equation   2 y = x -x - 2.
Not correct. Choice (c) is false.
Try again this is  y = 2x- x2.
Not correct. Choice (d) is false.
Try again, this graph is concave up.
Question 2 lion

Which of the following graphs represent  y = 2x2- 2x- 4 ?
a) PIC   b) PIC
c) PIC   d) PIC

 

Not correct. Choice (a) is false.
Try again, this is  y = x2+ 4x - 4.
Your answer is correct.
y = 2x2 -2x -4 = 2(x2- x -2)= 2(x- 2)(x +1)   so it is concave up and passes through  (-1 ,0)   and  (2,0)   and has  y -intercept  -4 .
Not correct. Choice (c) is false.
Try again, this is  y = -(x2- 4x+ 4).
Not correct. Choice (d) is false.
Try again, this is  y = -2x2+ 2x+ 4.
Question 3 lion

Consider the graph of  y = a(x - 1)2   below.

PIC
Which of the following statements about the graph is true?
a) The graph has a maximum and the coefficient of  (x- 1)2, a   is negative.
b) The graph has a minimum and the coefficient of  (x- 1)2, a   is negative.
c) The graph has a maximum and the coefficient of  (x - 1)2, a   is positive.
d) The graph has a minimum and the coefficient of  (x- 1)2, a   is positive.

 

Your answer is correct.
The graph is concave down so it has a maximum and  a   is negative.
Not correct. Choice (b) is false.
Try again, the graph has a maximum but you have the coefficient right.
Not correct. Choice (c) is false.
Try again, if the graph has a maximum then  a   must be negative.
Not correct. Choice (d) is false.
The graph is concave down so it has a maximum.
Question 4 lion

Consider the graph of  y = b0 + b1x+ b2x2   below.

PIC
Which of the following statements about the coefficients  b0   and  b2   is true?
a) b0 = -3 , b2 > 0.   b) b0 =- 2, b2 >0 .
c) b0 = -2, b2 < 0.   d) b0 =- 1, b2 <0 .

 

Not correct. Choice (a) is false.
Try again, you have the minimum not the  y -intercept for  b0.
Your answer is correct.
The  y -intercept is  -2 so  b0 = - 2   and the parabola is concave up so  b2 > 0.
Not correct. Choice (c) is false.
Try again, you have the wrong concavity.
Not correct. Choice (d) is false.
Try again, you have the wrong concavity and the wrong intercept.
Question 5 lion

Consider the graph of  2 y = b0 + b1x+ b2x   below.

PIC
Which of the following statements about the coefficients  b0   and  b2   is true?
a) b0 = 3, b2 > 0.   b) b0 = 2, b2 > 0.
c) b0 = 3, b2 < 0.   d) b0 = 2, b2 < 0.

 

Not correct. Choice (a) is false.
Try again, you have one of the  x -intercepts not the  y -intercept for  b0   and the wrong concavity.
Not correct. Choice (b) is false.
Try again, you have the wrong concavity.
Not correct. Choice (c) is false.
Try again, you have one of the  x -intercepts not the  y -intercept for  b0 .
Your answer is correct.
The  y -intercept is  2 so  b0 = 2   and the parabola is concave down so  b2 < 0.