Question

解方程x+2/7x=1/14 x/1/8=18*2/3 40%x+1/4=7/12下面各题怎么简便就怎样算7/2*5/8+3/2/8/5

1-5/8除25/28+3/10 (2/3-4/15*5/6)/二十一分之20 4/5除［(3/5-1/2)*2］

Answer 1

x+2/7x=1/14
解：9/7x=1/14
x=1/14*7/9
x=1/18
x/(1/8)=18*2/3
解：8x=12
x=12÷8
x=3/2
x=1.5
40%x+1/4=7/12
解：2/5x=7/12-1/4
2/5x=7/12-3/12
2/5x=1/3
x=1/3*5/2
x=5/6
1-5/8÷25/28+3/10——除以
=1-5/8*28/25+3/10
=1-7/10+3/10
=3/10+3/10
=6/10
=3/5

(2/3-4/15x5/6)/21分之20
=(2/3-2/9)x21/20
=(6/9-2/9)x21/20
=4/9x21/20
=7/15
4/5÷【(3/5-1/2)x2】——除以
=(4/5)÷(6/5-1)
=4/5÷1/5
=4/5x5
=4
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