38)
a)-3/4+5/6=(-9+10)/12=1/12
1/12-1/3=(1-4)/12=-3/12=-1/4
b) a=-5 1/4+(-11/5+1/10) =-21/4+(-22+1)/10=-21/4-21/10=
=(-105-42)/20=-147/20
b=(-21/4-2 1/5)+0,1=(-21/4-11/5)+1/10=(-105-44+2)/20=-147/20
a=b
c)x=-(1/3)³ -x=(1/3)³ -x=1/27
d)x=(-0,2)³ x=-0,008 x⁻¹ =1/x=1/-0,008=-125
39)
IxI<4 ⇒ a={0,1,2,3}
a/5∈{0,1/5,2/5,3/5}
40)
a) (1-1/3)×(0,5+1)=2/3×(1/2+1)=2/3×3/2=1 1²=1
b) (1-1/2)×(1-1/3)×(1-1/4)=1/2×2/3×3/4)=1/4 (1/4)³=1/64
c) (-1+2/3)⁻³ :a/b= (-1/3)⁻¹
(-1/3)⁻³:a/b=(-1/3)⁻¹
(-3)³ : a/b=-3
a/b=-27:(-3)=9
41.
ii aducem la acelasi numitor comun care este 60
1/2= 30/60
2/3=40/60
3/4=45/60
4/5=48/60
4/5 este mai mare deoarece au acelasi numitor si numaratorul este cel mai mare
