解:(1)0.52-x=0.25,
0.52-x+x=0.25+x,
0.25+x=0.52,
0.25+x-0.25=0.52-0.25,
x=0.27;
(2)x-0.15x=8.5,
(1-0.15)x=8.5
0.85x=8.5,
0.85x÷0.85=8.5÷0.85,
x=10;
(3)
:
=x:
,
x=
×
,
x×5=
×5,
x=
;
(4)
x+2.4×5=14,
x+12=14,
x+12-12=14-12,
x=2,
x×2=2×2,
x=4.
分析:(1)根據(jù)等式的性質(zhì),兩邊同加上x,得0.25+x=0.52,兩邊同減去0.25即可;
(2)運(yùn)用乘法分配律改寫成(1-0.15)x=8.5,即0.85x=8.5,兩邊同除以0.85即可;
(3)先根據(jù)比例的性質(zhì)改寫成
x=
×
,再根據(jù)等式的性質(zhì),兩邊同乘5即可;
(4)先求出2.4×5=12,再根據(jù)等式的性質(zhì),兩邊同減去12,再同乘2即可.
點(diǎn)評:此題考查了根據(jù)等式的性質(zhì)解方程,即等式兩邊同加、同減、同乘或同除以一個(gè)數(shù)(0除外),等式的左右兩邊仍相等;注意等號上下要對齊.