#### Answer

n=3$\frac{5}{6}$. This is between the integers 3 and 4.

#### Work Step by Step

In order to solve this algebraic expression, we must isolate the variable. A variable is the letter in the problem (for instance, in the equation x+2=10, x is the variable). Because addition and subtraction are inverse operations (they cancel each other out), we know we must add when a number is being subtracted from the variable and subtract when a number is being added to the variable.
In the equation 10.5=3n-1, we must get rid of the 1, which is on the same side as n, in order to solve. Thus, we add 1 on both sides of the equation to find that 3n=11.5. We then divide by 3 to find that n equals 3$\frac{5}{6}$. When we are using mental math, we can estimate, allowing us to determine that the value is between 3 and 4.