Question

if y=2x-8 what is the minimum value of the product xy

Answer 1

\[g(x)=x(2x-8)\implies g(x)=2x^2-8x\]

Answer 2

now maximize the function g(x)

Answer 3

i dont get why it turns into x(2x-8)

Answer 4

oh i get it nevermind

Answer 5

replace "y" :)

Answer 6

i cant remember how to maximiz3

Answer 7

at a maxima or minima, the first derivative is "0"
so, \(g'(x)=0\)
and solve for "x"

Answer 8

I got 2 is that correct

Answer 9

yes.

Answer 10

thank yout

Answer 11

now, check if g(x) is maxima or minima...

Answer 12

use the second derivative test to confirm g(x) has a maxima at x=2