Quadratic graphs - Quiz 1.

Quadratic Graphs

Questions

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attempt

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wrong

MathQuiz 4.2
University of Sydney
School of Mathematics
and Statistics
© Copyright 2004

Quadratic graphs - Quiz 1. Question

Question 1

Which of the following graphs represent $y = x2- 2x?$

Not correct. Choice (a) is false.

Try again, this is the line $y = x- 2.$

Not correct. Choice (b) is false.

Try again, this is the graph of the equation $2 y = x - x- 2.$

Your answer is correct.

$2 y = x -2x = x(x - 2)$ so it is concave up and passes through $(0,0)$ and $(2,0).$

Not correct. Choice (d) is false.

Try again, this graph is concave down.

Question 2

Which of the following graphs represent $2 y = 3 - 2x- x ?$

Not correct. Choice (a) is false.

Try again, this is $2 y = x + 4x+ 3.$

Your answer is correct.

$2 y = 3- 2x - x = (3 +x)(1- x)$ so it is concave down and passes through $(-3 ,0)$ and $(1,0).$

Not correct. Choice (c) is false.

Try again, this is $2 y = - (x - 4x +3).$

Not correct. Choice (d) is false.

Try again, this is $2 y = x - 4x+ 3.$

Question 3

Consider the graph of $2 y = ax$ below.
Which of the following statements about the graph is true?

Not correct. Choice (a) is false.

Try again, the graph does have a minimum but you have the coefficient wrong.

Not correct. Choice (b) is false.

Try again, the graph does not have a maximum.

Not correct. Choice (c) is false.

Try again, if the graph has a maximum then $a$ must be negative.

Your answer is correct.

The graph is concave up so it has a minimum and $a$ is positive.

Question 4

Consider the graph of $2 y = b0 +b1x + b2x$ below.
Which of the following statements about the coefficients $b0$ and $b2$ is true?

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

Which of the following graphs represents $y = b0 + b1x+ b2x2$ where $b0 = - 1$ and $b2 < 0 ?$

Your answer is correct.

Correct. All of the graphs have $b0 = - 1$ but only 1 and 4 are concave down, as required.

Not correct. Choice (b) is false.

Try again, 1 has $b2 < 0$ but 2 has $b2 > 0 .$

Not correct. Choice (c) is false.

Try again, 2 and 3 both have $b2 > 0.$

Not correct. Choice (d) is false.

Try again, 3 has $b2 > 0 .$