Question

find coordinates of x/ y intercept and max or mini point on the grapg of these quad fuction. show answer by obtaining reasoing with sumbolic forms
help:
9a ) f(x)=x(7-x)
d) f(x)=-(x-3)(x+5)
g) f(x)=2(x-3)(x-8)

Answer 1

you at least have the x,y intercepts?

Answer 2

i got nothing i got no idea how to do this

Answer 3

let's find those first.

Answer 4

ok

Answer 5

make x=0 and the value of y will give y-intercept. conversely true for x-intercept.

for maxima or minima, differentiate and equate the differential to 0. the values of x for which it's zero, gives point of maxima and minima!

Answer 6

write it out pelase

Answer 7

finding the y-intercept is easy. make x=0 and evaluate each function.

Answer 8

we went through the 2nd equation in quite a bit of detail.

Answer 9

so for a it would be written f(0)=0(7-0)

Answer 10

phi internet stopped working so lost everything we did

Answer 11

ok, do the same for the other two...

Answer 12

forget that. let's just work on one function first.

Answer 13

oaky

Answer 14

this quadratic function opens up so it will have a.... (max/min)

Answer 15

ok

Answer 16

can you answer? max or min?

Answer 17

no

Answer 18

y = x(7-x) = 7x -7x^2. the coefficient of the x^2 term will tell you if it's opening upward or downward. If the number is positive, it opens upward. if negative, then downward.

Answer 19

ok

Answer 20

does it open upward or downard?

Answer 21

up?

Answer 22

This is going to be a frown shape. So it will have a maximum peak.

Answer 23

ok

Answer 24

Can you find the y intercept?
f(0)=0(7-0)

Answer 25

would it be 0

Answer 26

That means multiply 0 times 7

Answer 27

its o

Answer 28

so you have the y-intercept. Now find the x-intercepts
f(x)=x(7-x)

what x values make this 0?
x(7-x)=0

Answer 29

0

Answer 30

and 7

Answer 31

ok you have the y-intercept = 0, you have 2 x-intercepts 0 and 7

now find the x where the parabola peaks. It is half way between the 2 x intercepts
add them together and divide by 2

Answer 32

3.5

Answer 33

dear take the second derivative of this function must be equal to zero, then if you get the positive answer then its minima and if you get the negative one then its maxima

Answer 34

now to finish, find what the f(3.5) value is:
f(x)=x(7-x)
f(3.5) = 3.5*(7-3.5)

Answer 35

how to solve that

Answer 36

first do (7-3.5)=?

Answer 37

3.5

Answer 38

now multiply
3.5*(7-3.5) = 3.5 * 3.5 =

Answer 39

igot a werid number

Answer 40

is it 12.25

Answer 41

?