1.因为a、b同号,所以答案只有一个:3
剩下是补充上一楼的:
3.(-3-4.5)-(-3
4.-6+(-3.5)+4=-5.5,6+3.5+4=13.5,13.5-5.5=8
5.甲=-10,甲比已高十米,乙=(-10)-10=-20,丙是乙的-1/2倍,丙=-1/2x(-20)=10,甲比丙高=-10-10=-20
1、7.5-2*1/3-22.5-6*2/3=7.5-31.5=-24
2、0.75-2.8-0.2-1.25=0.75-4.25=-3.5
3、-1/3*(-3)+2*1/2-3*1/3-5*1/6=1+2+3-5*1/6=5/6
4.-I-3/5+2/5I+I(-1/4)-1/2Ix(-2)=1/5+1/4x(-2)=1/5-1/2=-3/10
5、-27*9/11x1/9-(-6/12+8/12-9/12-11/12)x24=-27*1/11-(-18/12)x24=-27*1/11+36=8*10/11
6、-1*2/3x(-4*1/5)+17=(-5/3)x(-21/5)+17=7+17=24
7、39/12)-(-76/12)-27/12+40/12=39/12+76/12-27/12+40/12=128/12=10*2/3
8、-7x(-3/14)+3/8x16/9=3/2+2/3=2*1*6