First, you should know the order of operations:
PEMDAS
Parentheses
Exponents
Multiplication
Division
Addition
Subtraction
So with the problem you do the parentheses first
8+6(2c-1)
This being said, you solve the 6*(2c-1) first which equals 12c-6
8 +12c -6
12c +8 -6
12c + 2
