Answers and Step-by-step explanation:
12: The 5s are worth a lot more than the 2s. The 5s are worth fifty thousand and five thousand whereas the 2s are only worth two hundred and twenty.
13: She needs 4 forks (2000 - 1996 = 4)
She needs 255 knives (2000 - 1745 = 255)
She has 226 extra spoons ( 2116 - 2000 = 116)
The only rule to follow is
Divide dividend by divisor and the mention the quotient and things left after remains in place of remainder
Here is a sample

It is 105 degrees because the area of a triangle always adds up to 180
Given

subject to the constraint

Let

.
The gradient vectors of

and

are:

and

By Lagrange's theorem, there is a number

, such that


It can be seen that

has local extreme values at the given region.
First you have to set up your equation. 5x+80 and x+15.