NatureSmile NatureSmile 12-05-2017 Mathematics contestada -a + 1 =15 I solved all the other problems and the only number without and eqaution pair is -14. BUT -14 +1 is -13. AHHH how can -14 + 1= 15 be -a+1= 15. If you can't explain it can you please help me to find -a. Thanks