(1)(8.7+3.5)÷(8.7-3.5),
=12.2÷5.2,
=
61
26 .
答:商是
61
26 .
(2)设这个数是x;
3
4 x-4.5×
2
5 =6,
3
4 x-1.8=6,
3
4 x-1.8+1.8=6+1.8,
3
4 x=7.8,
3
4 x÷
3
4 =7.8÷
3
4 ,
x=10.4.
答:这个数是10.4.
(1)(8.7+3.5)÷(8.7-3.5),
=12.2÷5.2,
=
61
26 .
答:商是
61
26 .
(2)设这个数是x;
3
4 x-4.5×
2
5 =6,
3
4 x-1.8=6,
3
4 x-1.8+1.8=6+1.8,
3
4 x=7.8,
3
4 x÷
3
4 =7.8÷
3
4 ,
x=10.4.
答:这个数是10.4.