Answer:
Step-by-step explanation:
a) x=24
b) x=20
So, using our given information, we have a line of the equation

, or

. Plugging in our value 9 for

, we get

.
j=3
Answer:
x=-20/7 or -2.857
Step-by-step explanation:
bring like terms together in each side of the = side
then work the out
Let's say the numbers are "a" and "b"
thus

set the derivative to 0, and check the critical points, there's only one anyway
and do a first-derivative test, to see if it's a maximum