(1)(1+
)x=452 3
x=455 3
x÷5 3
=45÷5 3
5 3
x=27;
(2)
x+2 7
=764 5
x+2 7
-4 5
=76?4 5
4 5
x÷2 7
=752 7
÷1 5
2 7
x=263
;1 5
(3)(1-15%)x=170
85%x=170
85%x÷85%=170÷85%
x=200.