1. a) 7.5 - (-3.7) = 7,5+3,7 = 11,2;
в) 7 1/4 - 8 2/9 = 29/4 - 74/9 = 261/36-296/36 = -35/36;
г) -8 5/12 - (-7 13/15) = -101/12+118/15 = 1515/180 - 1416/180=99/180=0,55;
2.
a) 7.8 - x = 9.3
х=9,3-7,8
х=1,5
б) y - (- 17.85) = 12
у+17,85=12
у=12-17,85
у=-5,85