399 because k^2 is 81 and multiply that by 5, you get 405 and subtract 6 to get 399
Answer,
So, basicly they are asking you to imput, "9" for where the letter "K" is.
Let's do that,
5 * 9^2 - 6
Now we will simplify 9^2,
9 x 9 = 81
Simplify,
5 x 81 = 405
Now, subtract
405 - 6 = 399
