Đáp án:
Giải thích các bước giải
Bài 2
A) 6 4/5-(1 2/3+3 4/5)
= 34/5-(5/3+19/5)
= -5/3+(34/5-19/5)
= -5/3+15
= 40/3
e)-3/5.5/7+(-3/5).3/7+(-3/5).6/7
= -3/5.(5/7+3/7+6/7)
= -3/5.2
= -6/5
f)1/3.4/5+1/3.6/5-4/3
= 1/3.(4/5+6/5)-4/3
= 1/3.2-4/3
= 2/3-4/3
= -2/3
Bài 3
a)x/5=2/3=> 5.2=x.3=15=x.3=>x=15:3=5
Vậy x=5
b)x/3-1/2=1/5
x/3 =1/5+1/2
x/3 =7/10
x/3=7/10=>3.7=x.10=21=x.10=>x=21:10=2,1
Vậyx=2,1
p)(5x-1)[-1/2x+5]=0
x.[5-1/2]-1+5=0
x.9/2-1 =0-5
x.9/2-1 =-5
x.9/2 =-5+1
x.9/2 =-4
x =-4:9/2
x =-8/9
Vẫy=-8/9