Đáp án:
a)x/5=2/3
=>x=5x2/3
=>x=10/3
b)x/3-1/2=1/5
=>x/3=1/5+1/2
=>x/3=7/10
=>x=3x7/10
=>21/10
c)x/5+1/2=6/10
=>x/5=6/10-1/2
=>x/5=1/10
=>x=5x1/10
=>x=1/2
d)x/5+1/2=6/10(giống câu c)
e)x+3/15=1/3
=>x+3=15x1/3.
=>x+3=5
=>x=5+3
=>x=8
f)x-12/4=1/2
=>x-12=4x1/2
=>x-12=2
=>x=2+12
=>x=14
h)(3x-1)(-1/2x+5=0
=>3x-1=0
-1/2x+5
=>3x=1
-1/2x+5=0
=>x=1/3
-1/2x=-5
=>x=1/3
x=10
i)3/4-x=1/3
=>-x=3/4-1/3
=>-x=5/12
k)-5/6-x=2/3
=>-x=-5/6-2/3
=>-x=-3/2
l)-2/3-1/3(2x-5)=3/2
=>-2/3-2/3x-(-5/3)=3/2
=>-2/3-2/3x+5/3=3/2
=>-2/3+5/3-2/3x=3/2
=>-2/3x=3/2
=>x=3/2:(-2/3)
=>x=-9/4
m)1/2x+1/2=5/2
=>1/2x=5/2-1/2
=>1/2x=2
=>x=2:1/2
=>x=4
n )x-5/9=-2/3
=>x=-2/3+5/9
=>x=-1/9
CHÚC BẠN HỌC TỐT NHA<3
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