# Homework Help: I'v quistion on Quadratic Functions

1. Mar 12, 2010

### megatronic

1. The problem statement, all variables and given/known data
Let f(x)= 125x-6x2 find the maximum value of f to four decimal places graphically

2. Relevant equations
(x)= 125x-6x2

3. The attempt at a solution
1. The problem statement, all variables and given/known data

attempt solution:

x=-b+$$\sqrt{}b2-4ac$$/2a

x=-125+$$\sqrt{}1252-4(-6)(0)$$/2a

x= 0/-12=0

x=-b-$$\sqrt{}b2-4ac$$/2a

x=-b-$$\sqrt{}b2-4ac$$/2a

x=(-125-125)/-12

x=-125/6

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited: Mar 12, 2010
2. Mar 12, 2010

### snshusat161

Do you know how to make graph for quadratic equations?

3. Mar 12, 2010

### snshusat161

and also show your attempt otherwise nobody will help you here because of the rules of PF

4. Mar 12, 2010

### megatronic

ya I know to make graph for quadratic

5. Mar 12, 2010

### Mentallic

Ok then, do you realize there is a symmetry of any parabola on either end of its max/min? So if you find the roots of the quadratic, what can you deduce about the coordinates of the max/min from that?

6. Mar 12, 2010

### Staff: Mentor

What you've done is attempt to find the x-intercepts, which is not at all what this problem is asking for. In addition, there is one intercept that you did not find, and the one you found is incorrect.

7. Mar 12, 2010

### Angry Citizen

Think what 'maximum' is. Note that maximum does not refer to an x value.

There is a formula to determine the maximum or minimum value of a parabola. Give it a hard think. It'll come to you.

8. Mar 12, 2010

### Staff: Mentor

The OP is not supposed to use a formula. He/she is supposed to find the maximum by looking at a graph of the function.