Answer:
Step-by-step explanation:
Given
Suppose side face have a dimension of l\times l
and width of h
volume 
volume 
Area of side wall is 
Area of top Wall 
Area of bottom 
Cost of bottom wall 
Cost of top wall 
Cost of side walls 
total cost 
differentiate C w.r.t l to get minima or maxima
Dimension of Box is
5x+100=10x
-5x on both sides (10x-5x=5x)
100=5x
divide by 5 on both sides (100/5= 20)
20=x
13. 1
14. 1
15. any number and 0 will have a quotient of 0.
for example 7/0=0 . 8/0=0 . 9/0=0
if you try and check your work using multiplication 7*0=0 . 8*0=0 . 9*0=0
then you will realize the rule is right
5 night’s because you should divide 3 chapters by 3 over 5
P-paratheses (do any math that has parentheses around the numbers) y=(2x5)+25
E-exponents (do the exponents next) y=(2x5)+5^2
M-multiplying. (Basically everything is self explanatory from here to then cuz im lazy to list examples)
Just basically if you don't use PEMDAS, you'll get the wrong answer
