To solve for x, we need to isolate it on one side of the equation.

First, let's simplify the equation by finding a common denominator for the fractions. The common denominator for 20 and 15 is 60.

-13/20 + x = -11/15

Next, we need to convert the fractions to have the same denominator of 60.

-13/20 can be converted to -39/60 by multiplying the numerator and denominator by 3.

-11/15 can be converted to -44/60 by multiplying the numerator and denominator by 4.

Now, the equation becomes:

-39/60 + x = -44/60

To eliminate the fractions, we can subtract -39/60 from both sides of the equation:

x = -44/60 + 39/60

Simplifying the right side of the equation:

x = -5/60

The final answer is x = -5/60.