解比例.
|
(1)x:42=
:10,5 7
10x=42×
,5 7
10x=30,
10x÷10=30÷10,
x=3;
(2)
=x 2.4
,15 0.8
0.8x=2.4×15,
0.8x=36,
0.8x÷0.8=36÷0.8,
x=45;
(3)
:x=1 2
:6,3 4
x=3 4
×6,1 2
x=3,3 4
x÷3 4
=3÷3 4
,3 4
x=4.
解比例.
|
(1)x:42=
:10,5 7
10x=42×
,5 7
10x=30,
10x÷10=30÷10,
x=3;
(2)
=x 2.4
,15 0.8
0.8x=2.4×15,
0.8x=36,
0.8x÷0.8=36÷0.8,
x=45;
(3)
:x=1 2
:6,3 4
x=3 4
×6,1 2
x=3,3 4
x÷3 4
=3÷3 4
,3 4
x=4.