数学简便题:(0.75-3/16)*(2/9+1/3) x+3/7=3/4

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数学简便题:(0.75-3/16)*(2/9+1/3) x+3/7=3/4

数学简便题:(0.75-3/16)*(2/9+1/3) x+3/7=3/4
数学简便题:
(0.75-3/16)*(2/9+1/3) x+3/7=3/4

数学简便题:(0.75-3/16)*(2/9+1/3) x+3/7=3/4
(0.75-3/16)*(2/9+1/3)
=(3/4-3/16)*(2/9+1/3)
=3*(4/16-1/16)*(2/9+3/9)
=3 *3/16*5/9
=5/16
x+3/7=3/4
则x=3/4-3/7=3*(1/4-1/7)=3*(7/28-4/28)=3*3/28=9/28
所以x=9/28

(0.75-3/16)*(2/9+1/3)
=(3/4-3/16)*(2/9+1/3)
=(12/16-3/16)*(2/9-1/3)
=9/16*(2/9-1/3)
=9/16*2/9-9/16*1/3
=1/8-3/16
=2/16-3/16
=-1/16