Question

a) tìm x , biết \(\dfrac{3}{7}x+\dfrac{1}{3}=\dfrac{1}{2}\)

b)tìm x, y  biết \(\dfrac{x}{2}=\dfrac{y}{-3}\) và x +2y = 12

c) tìm x , biết \(\dfrac{x+2016}{5}-\dfrac{x+2016}{3}=\dfrac{x}{2}+1008\)

Answer 1

`a)3/7x+1/3=1/2`

`=>3/7x=1/2-1/3=1/6`

`=>x=1/6:3/7`

`=>x=7/18`

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`b)` Áp dụng t/c của dãy tỉ số bằng nhau có:

   `x/2=y/[-3]=[x+2y]/[2-6]=12/[-4]=-3`

`@x/2=-3=>x=-6`

`@y/[-3]=-3=>y=9`

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`c)[x+2016]/5-[x+2016]/3=x/2+1008`

`=>[6(x+2016)]/30-[10(x+2016)]/30=[15x]/30+30240/30`

`=>6x+12096-10x-20160=15x+30240`

`=>19x=-38304`

`=>x=-2016`