Quadratic functions

Which of the following relations (functions) is quadratic?

• y = 3x -2

• y = x² +3x -4

• y = (x+2)² -3

• y = (2x²+1)²

• y = x(x+3)²

Which is quadratic function?

• y= (2x+3)(x+1)

• y = x² - 5x - 6

• y = x³ -2x² +3x +1

• y = 3x + 5

• y = x² + 2x + (1-x)(1+x) + 4

Which of the following functions represents a parabola?

• y = 3x +2

• x² + y² = 9

• y = (x-1)²

Antoine throws a ball to his dog, who will catch the ball at a height of 1 meter above ground. The ball's height (in meters above the ground), x seconds after Antoine threw it, is modeled by: h(x)=−2x² + 9.8x + 2

How many seconds after being thrown will the dog catch the ball?

Antoine throws a ball to his dog, who will catch the ball at a height of 1 meter above ground. The ball's height (in meters above the ground), x seconds after Antoine threw it, is modeled by: h(x)=−2x² + 4x + 48

What is the maximum height that the ball can reach?

A farmer wants to make a rectangular pen for his sheep. He has 100m fencing material to cover three sides with the other side being a brick wall. How should he choose the width of the pen to maximize the space for his sheep?

The number of mosquitoes in Anchorage, Alaska (in millions of mosquitoes) as a function of rainfall (in centimeters) is modeled by: m(x)=-x²+14x

How many centimeters of rain will produce the maximum number of mosquitoes?

Find the equation of parabola passing through the points: (1,0) ; (3,-4) and (4,-3)

• y = x² -2x + 1

• y = x² - 6x + 5

• y =x² - 2x -7

• y = x² - 7x +9

Find the equation of parabola passing through the points: (1,0) ; (2,1) and (0,-3)

• y = x² -2x - 3

• y = x² - 4x + 1

• y =x² - 2x + 1

• y = -x² + 4x - 3

Which is the equation of symmetry line (axis) of the parabola represented by: y = x² +4x -3?

• y = - 2

• x = -2

• x = 2

• y = 2