plz any body could do this question for me?

Question

y=2x^3 -30x^2 +96x +7

(i) What value of x corresponds to the minimum?
(ii) What is the corresponding minimum value of y?
(iii) What value of x corresponds to the maximum?
(iv) What is the corresponding maximum value of y?
(v) What value of x corresponds to the point of inflexion?

Answer 1

take derivative of that function
y'=6x^2-60x+96
set y'=0 => 6x^2-60x+96=0 =>(x-8)(x-2)=0
therefore x=8 and x=2
use sign chart
-infinity.................2........ 8....................infinity
+ ................. .- .........................+.......
from the sign chart you see from -infinity to 2 they increase then decreased
therefore x=2 is maximum, similiar to that x=8 is minimum
if you want t o find y . then just put x=2 in the original function to have the answers
. i> x=8
ii>y= -121
iii> x=2
iv>y=95
v> take the second derivative then set that equal 0
y"=12x-60 =0 =>x=60/12 =5 and y=-13 good luck

Answer 2

Find the differential of the equation and you will be able to solve the problems easily.

Answer 3

14 that's the answer to all five questions

Answer 4

You should get a tutor.

Answer 5

go and ask your maths teacher