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2.6 Concept Review

Concept Review: Quadratic Equations and Functions


    1. Solve [latex]5x^2-45=0[/latex] three different ways using each of our three methods for solving quadratic equations.
    2. Pick which method from part (a) you prefer, and briefly explain why you prefer it.
  1. After a rocket is launched, it follows the flight path given by the function [latex]f\left(t\right)=-16t^2+9t.[/latex]
    1. Find the height from which the rocket was launched.
    2. Find the maximum height of the rocket.
    3. Find when the rocket hits the ground.
  2. After a rocket is launched, the path of the rocket is given by the function [latex]g\left(t\right)=-16t^2+9.[/latex]
    1. Find the y-intercept, and describe what it represents in this problem.
    2. Find the vertex, and describe what it represents in this problem.
    3. Find the x-intercept, and describe what it represents in this problem.
  3. How would you explain the differences in your answers for problems 2 and 3 above in the context of time and height?
  4. Let [latex]f\left(x\right)=x^2-81[/latex] and [latex]g\left(x\right)=x^2+81.[/latex]
    1. Explain the difference between the equations [latex]f\left(x\right)=0[/latex] and [latex]g\left(x\right)=0[/latex]
    2. Explain how to find the solutions [latex]f\left(x\right)=0[/latex] and [latex]g\left(x\right)=0[/latex]
    3. Can you use all three quadratic methods to solve [latex]g\left(x\right)=0[/latex]? Why or why not?
  5. Solve [latex]\frac{x^2}3-\frac{35}6=\frac x2[/latex]
  6. When solving a quadratic equation using the quadratic formula, how many and what kind of solution(s) do you get if the discriminant (inside the square root) is
    1. positive?
    2. negative?
    3. zero?
  7. Create a quadratic equation that has solutions [latex]x=5[/latex] and [latex]x=-8[/latex]
  8. Create a quadratic equation that has imaginary solutions. Be sure to show work and explain your reasoning.

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