Answer:
598 books
Step-by-step explanation:
Let x be the number of books in the 3rd pile. We will have then:
1st pile: 2x + 10
2nd pile: 2x
3rd pile: x
3000 = (2x + 10) + (2x) + (x)
3000 = 5x + 10
3000 - 10 = 5x
2990 = 5x
2990/5 = x
x = 598 books in the third pile!
We can check that:
3000 = 2*598 + 10 + 2*598 + 598
3000 = 1196 + 10 + 1196 + 598
3000 = 3000 CHECK!
In order to solve this we must first,
Subtract both sides of the equation by 10,
y-10=1/2x
Now we have to multiply both sides by 2 so that only x is left.
2y-20=x
Therefore, x=2y-20
1 2/3y = 3x
A picture is worth a thousand words

Differentiate both sides, treating
as a function of
. Let's take it one term at a time.
Power, product and chain rules:



Product and chain rules:




Product and chain rules:




The derivative of 0 is, of course, 0. So we have, upon differentiating everything,

Isolate the derivative, and solve for it:


(See comment below; all the 6s should be 2s)
We can simplify this a bit by multiplying the numerator and denominator by
to get rid of that fraction in the denominator.
