三道数学题 速回!1.简算: (-5/6+2/3)÷(-7/12)*3 2. 已知丨3-y丨+丨x+y丨=0 求x-y/xy 的值 3.已知ab互为倒数,cd互为相反数,求ab/5+31/197*(c+b)的值
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![三道数学题 速回!1.简算: (-5/6+2/3)÷(-7/12)*3 2. 已知丨3-y丨+丨x+y丨=0 求x-y/xy 的值 3.已知ab互为倒数,cd互为相反数,求ab/5+31/197*(c+b)的值](/uploads/image/z/918847-55-7.jpg?t=%E4%B8%89%E9%81%93%E6%95%B0%E5%AD%A6%E9%A2%98+%E9%80%9F%E5%9B%9E%211.%E7%AE%80%E7%AE%97%EF%BC%9A++%EF%BC%88-5%2F6%2B2%2F3%EF%BC%89%C3%B7%EF%BC%88-7%2F12%EF%BC%89%2A3++++++++++++2.++%E5%B7%B2%E7%9F%A5%E4%B8%A83-y%E4%B8%A8%2B%E4%B8%A8x%2By%E4%B8%A8%3D0++++%E6%B1%82x-y%2Fxy+%E7%9A%84%E5%80%BC+++++++++3.%E5%B7%B2%E7%9F%A5ab%E4%BA%92%E4%B8%BA%E5%80%92%E6%95%B0%2Ccd%E4%BA%92%E4%B8%BA%E7%9B%B8%E5%8F%8D%E6%95%B0%2C%E6%B1%82ab%2F5%2B31%2F197%2A%EF%BC%88c%2Bb%EF%BC%89%E7%9A%84%E5%80%BC)
三道数学题 速回!1.简算: (-5/6+2/3)÷(-7/12)*3 2. 已知丨3-y丨+丨x+y丨=0 求x-y/xy 的值 3.已知ab互为倒数,cd互为相反数,求ab/5+31/197*(c+b)的值
三道数学题 速回!
1.简算: (-5/6+2/3)÷(-7/12)*3 2. 已知丨3-y丨+丨x+y丨=0 求x-y/xy 的值 3.已知ab互为倒数,cd互为相反数,求ab/5+31/197*(c+b)的值
三道数学题 速回!1.简算: (-5/6+2/3)÷(-7/12)*3 2. 已知丨3-y丨+丨x+y丨=0 求x-y/xy 的值 3.已知ab互为倒数,cd互为相反数,求ab/5+31/197*(c+b)的值
(-5/6+2/3)÷(-7/12)*3
=(5/6-2/3)*12/7 *3
=5/6*12/7 *3 -2/3*12/7 *3
=30/7-24/7
=6/7
丨3-y丨+丨x+y丨=0
3-y=0 x+y=0
x=-3 y=3
x-y/xy =(-3-3)/(-3*3)=(-6)/(-9)=2/3
已知ab互为倒数,ab=1
cd互为相反数,c+d=0
ab/5+31/197*(c+b)=1/5+31/197*0=1/5
9/16,2/3,0.2
*这代表次方还是相乘?
6/7,2/3,1/5
1)6/7
2)x=-3,y=3,原式=2/3
3)ab=1,c+d=0
原式=1/5+31/197·0=1/5
1、6/7
2、2/3
3、题目有问题,如公式中c+b为c+d的话则为1/5