The answer would be "-3/8 + -1/10."
Simplify means to reduce so in this case we aren't solving the question we are reducing it into simpler terms.
[tex]-\frac{3}{8} -\frac{1}{10}[/tex]
According to the rules of KCC (Keep Change Change) you would have to turn the subtraction sign into a addition sign and make the positive 1/10 into a negative.
[tex]-\frac{3}{8} +-\frac{1}{10}[/tex]
The equation cannot be reduce no further therefore that would be your answer.
Hope this helps.