Simplify the expression. -1/8 - 2/7 = a. -1/8 b. 23/56 c. -23/56 d. 1/5

Since one number is negative and one is not and it is asking us to subtract, we have to make the second fraction a negative and add them together. 
We can multiply 7 and 8 to get a common denominator and so we now have -7/56 + -16/56. 
We can now add the negatives together to get -23/56 as your final answer.

Ithink your answer is c mark me brainliest