Answer:
Associative property - addition
Step-by-step explanation:
When three or more numbers are added, the sum is the same regardless of the way in which the numbers are grouped.
(6+2) + 5 = 6 + (2+5)
8 + 5 = 6 + 7
13 = 13
x will represent the first unknow number
6x will represent the second number
the two numbers together will equal 21
6x + x = 21 combine like terms
7x =21 divide both sides by 7
x =3
Hope that helps.
brainliest is always appreciated.
A + 2c - 5b - c + a - b
We're gonna have to combine like terms.
(a+a)+(-5b-b)+(2c-c)
2a-6b+c This is your answer