Question

Find the min/max of f(x)=5x^2+30x+49

Answer 1

find f'(x) and equate it to 0 to find the critical points.

Then find f''(x) and then find the value of f''(x) at these points if the value is >0 then the point is minima and if the value is <0 then the point is maxima

Answer 2

This is not for calculus this is for algerbra we don't do derivatives...

Answer 3

Then I m sorry because I know only this method

Answer 4

actually you are only looking for the vertex

Answer 5

Critical points is the best method. But you're looking for the vertex.

Can you factor this function? ;-)

Answer 6

you only have a min value

Answer 7

Darn it precal... -_- lol

Answer 8

now find f(-3) and that is your y value of your vertex

Answer 9

On sidenote, if you have a quadratic function
\[f(x) = ax^{2} + bx + c\]
Where a is not 0, then
if a>0, you will only have a minimum value for y
if a<0, you will only have a maximum value for y

Answer 10

instructions were probably given (as general) to a group of problems, teacher is probably trying to determine if student understands the difference between a min or max in quadratics

Answer 11

I understand, but good to know those, anyway, right? :)

Answer 12

yes, in calculus max and min can be used as local max or local min or absolute max or absolute min

Answer 13

we use that too in precal @terenzreingz

Answer 14

But thanks for your help everyone! I really do appreciate it :)

Answer 15

anytime :)