You can put this solution on YOUR website! 2k-b
Means do 2 times(multiplied by) whatever k is then take away the value of b.
Because k is 6(k=6) do 2*6 = 12
Then take away the value of b(b=4)
so 12 take 4(12-4) is 8
(In algebra letters stand for numbers, each letter stands for a different number. Whenever there's a number in front of a letter it means times the number by the value given for the letter.
If there are two letters times the values of the letters together).