It is -7.83 because you distribute the -6 to the n and the 1 inside the parentheses which makes you get -6n-5=42. Since 5 is negative you add it to -5 and the 42 on the other side of the equation which turns out to -6n=47. You then divide -6 on both sides of the equation. -6n divided by -6 cancels out so 47 divided by -6 equals -7.83333333 which rounds to -7.8