Question

evaluate each variable when n+12

20-n

n+6

Answer 1

n+12 = 20-n
take all same terms on one side
2n=4
n=2

Answer 2

Evaluating algebraic expressions can be a simple process,
but needs to follow an order of operations to get the right answer.
The sequence details the order you follow to
add, subtract, multiply, and divide. The order is:

P.E.M.D.A.S.
Parenthesis | Exponents | Multiplication | Division | Addition | Subtraction

1.Perform the operations inside a parenthesis first
2.Then exponents
3.Then multiplication and division, from left to right
4.Then addition and subtraction, from left to right
5.You can also create a little phrase to memorize, as the sequence:
Please Excuse My Dear Aunt Sally

Use this to help you answer your question.

Answer 3

do the same for the next one
im not sure if thats correct