Step-by-step explanation:
the filled in circles are for anything less than or equal to or greater than or equal to.
Answer: x = 9
Explanation:
the base must be raised
for example
55 = n ( the base is 10 ), then
55 = 
Answer:
558
Step-by-step explanation:
I can't say :>
Sometimes it will, and sometimes it won't.
I reason as follows:
(21 + x) + (30 + 2x) = 51 + 3x has an 'x' term
(42 + x) + (30 - x) = 72 has no 'x' term.