a, 5/3 + (-2/7) -(-1,2)
=5/3 + (-2/7) + 1,2
=271/105
b,1/2 - (-1/3) +1/23 +1/6
=1/2 + 1/3 +1/23 +1/6
=24/23
c,-24/11 + (-19/13) +2/11 + (-20/13)
=(-24/11 + 2/11) + (-19/13 -20/13)
=-2 +(-3)
=-5
d,(8-9/4+2/7)-(-6-3/7+5/4)-(3+2/4-9/7)
=8-9/4+2/7 + 6 + 3/7 -5/4 -3-2/4+9/7
=(8+6-3) + (-9/4-5/4-2/4)+(2/7+3/7+9/7)
=11+(-4)+2
=9
Bài 2: a, x+2/3=3/5 -(-1/6)
x+2/3=23/30
x=1/10
b,7/4-(x+5/3)=-12/5
7/4-x-5/3=-12/5
-x-1/12=-12/5
-x=-139/60
x=139/60
c,1/3-x=5/6-1/4
1/3-x=7/12
x=-1/4
d,9/2-(2/3-(x+7/4))=-5/4
9/2-(2/3-x-7/4)=-5/4
9/2-2/3+x+7/4=-5/4
x+67/12=-5/4
x=-41/6
Anh làm hơi tắt có gì em trình bày thêm nhé