Quadratic Equations and Inequalities question about properties of quadratic

In summary, the question is about graphing a quadratic function with the given equation and finding its domain and range. The axis of symmetry is used to find the vertex, which is at (-3/2, 2). The other points of the parabola are (-1/2, 3), (0, -3), and (-2, 0). The graph is an upside down parabola with a domain of all real numbers and a range of {y|y≤25/8}. The correct axis of symmetry is x=-3/4 and the maximum value of F is at (-3/4, 25/8).
  • #1
ben328i
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0
[SOLVED] Quadratic Equations and Inequalities question about properties of quadratic

so here is the question

graph the function. state the domain and range of the function.

F(x)=-2x^2-3x+2

i try and use the axis of symmetry (-b/2a) and then plug that into the original formula to get the vertex.
i keep getting F(-3/2)=2

but then when i try and plug in numbers into the formula there scattered everywhere

F(-3/2)=2 is the vertex in the graph but i can't find the other points to show where the parabola is going

i tried -1/2, 0, -2 and got
(-1/2,3)
(0,-3)
(-2,0)

please help me out.

its supposed to be a upside down parabola with a domain of all real number and a range of {y|y<_ 25/8}

<_ = less than or equal to.
 
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  • #2
ben328i said:
so here is the question

graph the function. state the domain and range of the function.

F(x)=-2x^2-3x+2

i try and use the axis of symmetry (-b/2a) and then plug that into the formula for the vertex. i keep getting F(-3/2)=2
Which is correct.

Your axis of symmetry is, however, x=-3/4.

The maximum value of F is therefore:
[tex]F(-\frac{3}{4})=-2(-\frac{3}{4})^{2}-3*\frac{-3}{4}+2=\frac{-18}{16}+\frac{9}{4}+2=\frac{50}{16}=\frac{25}{8}[/tex]
 
  • #3
ughhhh i put -1 for a not -2
thanks.
 

1. What is a quadratic equation?

A quadratic equation is an equation of the form ax^2 + bx + c = 0, where a, b, and c are constants and x is the variable. It is called a quadratic equation because the highest power of x is 2.

2. What are the properties of quadratic equations?

Quadratic equations have the following properties:
- The graph of a quadratic equation is a parabola.
- The solutions to a quadratic equation can be found using the quadratic formula or by factoring.
- The discriminant (b^2 - 4ac) can be used to determine the number of solutions and the nature of the solutions (real or complex).
- Quadratic equations can have one, two, or no real solutions.
- The axis of symmetry of a parabola is given by x = -b/2a.
- The vertex of a parabola is given by the coordinates (-b/2a, f(-b/2a)), where f(x) = ax^2 + bx + c.

3. How do you solve a quadratic equation algebraically?

To solve a quadratic equation algebraically:
1. Put the equation in standard form (ax^2 + bx + c = 0).
2. Determine the values of a, b, and c.
3. Use the quadratic formula (x = (-b ± √(b^2 - 4ac)) / 2a) to find the solutions.
4. Simplify the solutions, if necessary.

4. How do you graph a quadratic equation?

To graph a quadratic equation:
1. Find the coordinates of the vertex using the formula (-b/2a, f(-b/2a)).
2. Determine the axis of symmetry by finding the x-coordinate of the vertex.
3. Plot the vertex and the axis of symmetry on the graph.
4. Use other points to draw the parabola, such as the x-intercepts (found by solving the equation) and other points on the parabola.
5. Label the graph and check for accuracy.

5. What are quadratic inequalities?

Quadratic inequalities are inequalities that involve quadratic expressions. They are solved in the same way as quadratic equations, by finding the values of x that make the inequality true. The solutions can be represented on a number line or graphed on a coordinate plane. Inequalities involving quadratic expressions can also involve absolute value, making the solutions more complex.

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