To multiply a number, simply take a number (Let's say 4) and another number (Let's say 3). If you multiply 4 by 3, you are simply taking the number 4, and adding it to itself 3 times (4 + 4 + 4).
I hope this makes sense, please tell me if you need some more information.
Hope this helps!
Answer:

Step-by-step explanation:
-5+2(10b-2)=31
Expand brackets.
-5+20b-4=31
-9+20b=31
Add 9 on both sides.
20b=40
Divide both sides by 20
b=2
Answer:
62.8 m^2
Step-by-step explanation:
The volume of a cylinder is given by
V = pi r^2 h where r is the radius and h is the height
V = (3.14) ( 2)^2 *5
V = 62.8 m^2

Solution ~
or it can also be expressed as ~
Answer:
Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool. Boy I am cool.
Step-by-step explanation: