解方程. 1-25%x=0.75; 3/4x−25%x=10; 2x−1/8×4=2/3.
问题描述:
解方程.
1-25%x=0.75;
x−25%x=10;3 4
2x−
×4=1 8
. 2 3
答
(1)1-25%x=0.75
1-25%x+25%x=0.75+25%x
1=0.75+25%x
1-0.75=0.75-25%x-0.75
0.25=25%x
0.25÷25%=25%x÷25%
x=1;
(2)
x-25%x=103 4
x=101 2
x÷1 2
=10÷1 2
1 2
x=20;
(3)2x−
×4=1 8
2 3
2x-
=1 2
2 3
2x-
+1 2
=1 2
+2 3
1 2
2x=
7 6
2x÷2=
÷27 6
x=
.7 12