(8 5/27-х)-2 25/27=1 25/27
8 5/27-х-2 25/27=1 25/27
-х=1 25/27+2 25/27-8 5/27
-х=4 23/27-8 5/27
-х=-3 10/27
х=3 10/27
2. а) 12m + 14m + 4,2 =12
26m=7.8
m=7.8:26
m=0.3
b) (9,8 - x) : 9 =0,7
9.8-x=0.7*9
9.8-x=6,3
-х=6,3-9,8
х=3,5
3. 15,81 : (24 - 23,66) - 18 : 37,5=
=15,81 : 0,34 - 18 : 37,5=
=46,5-0,48=
=46,02
4. а) 45^2-44^2=(45-44)(45+44)=1*99=99
b) 18^2+21^2=324+441=765
в) 37+32^2=37+1024=1061
г) 4*11^2=4*121=484
12345,12354,12435,12453,12534,12543,13245,13425,13452,13524,13542,14235,14325,14253,14352,14523,14532,15234,15324,15243,15342,15423,15432,21345,21354,21435,21453,21534,21543,23145,23154,23415,23451,23514,23541,24135,24153,24315,24351,24513,24531,25134,25143,25314,25341,25413,25431,31245,31254,31425,31452,31524,31542,32145,32154,32415,32451,32514,32541,34125,34152,34215,34251,34512,34521,35124,35142,35214,35241,35412,35421,41235,41253,41325,41352,41523,41532,42135,42153,42315,42351,42513,42531,43125,43152,43215,43251,43512,43521,45123,45132,45213,45231,45312,45321,51234,51243,51324,51342,51423,51432,52134,52143,52314,52341,52413,52431,53124,53142,53214,53241,53412,53421,54123,54132,54213,54231,54312,54321. Всего:119 чисел.