问题
解答题
求未知数x. (1)4-16x=1 (2)
(3)
(4)
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答案
(1)4-16x=1
4-16x+16x=1+16x,
1+16x=4,
1+16x-1=4-1,
16x=3,
16x÷16=3÷16,
x=
;3 16
(2)
:2 5
=x:(16-5),2 15
x=2 15
×11,2 5
x×2 15
=15 2
×11×2 5
,15 2
x=33;
(3)
x-3 5
x=13 10
,5 7
x=3 10
,12 7
x×3 10
=10 3
×12 7
,10 3
x=
;40 7
(4)
=3x-1 2x+1
,5 6
6×(3x-1)=5×(2x+1),
18x-6=10x+5,
18x-6+6=10x+5+6,
18x=10x+11,
18x-10x=10x+11-10x,
8x=11,
8x÷8=11÷8,
x=
.11 8