-543+485=485-543=-58
7.5-(-3.5)=7.5+3.5=11
0.54+(-0.83)=0.54-0.83=-0.29
-2.3-6.2=-8.5
-1.304+(-2.7)=-1.304-2.7=-4.004
45.25-50=-4.75
2.
-3.2+х=5.2
х=5.2+3.2=8.4
-3.2+8.4=5.2
5.7-х=8.9
х=5.7-8.9
х=-3.2
5.7-(-3.2)=5.7+3.2=8.9
6.7+у=-4.3
у=4.3-6.7
у=-2.4
6.7+(-2.4)=6.7-2.4=4.3
у-(-5)=3.2
у+5=3.2
у=3.2-5
у=-1.8
-1.8-(-5)=-1.8=5=3.2
3.
-6.1-(-3)=6.1-3=3.1
8.1+5=13.1
8.3-2.1=6.2
4.х+2=5
х=5-2=3