7/9x(-8/9)+2/9x(-8/9) 2/3x(-5/8)-(-1/3)x(-5/8)
问题描述：
7/9x(-8/9)+2/9x(-8/9) 2/3x(-5/8)-(-1/3)x(-5/8)
7/9x(-8/9)+2/9x(-8/9) 2/3x(-5/8)-(-1/3)x(-5/8) -9除以3+(1/2-2/3)x12+3的2次方用简便方法算_
答
7/9x(-8/9)+2/9x(-8/9)=(-8/9)×（7/9+2/9）=-8/92/3x(-5/8)-(-1/3)x(-5/8)=(-5/8)× （2/3+1/3）=-5/8-9÷[3+(1/2-2/3)x12+3 ²]=-9÷[3+(-4)+9] =9/8