Tìm x a,2.(3x+1)+1/2.3/5=-3/2 b,4-3/4.(2x+1)³=38/9

2 bình luận về “Tìm x a,2.(3x+1)+1/2.3/5=-3/2 b,4-3/4.(2x+1)³=38/9”

1. Giải đáp +Lời giải và giải thích chi tiết

    a)2(3x+1)+1/2 .3/5=-3/2

   <=>2(3x+1)+3/10=-3/2

   <=>2(3x+1)=-3/2-3/10

   <=>2(3x+1)=-9/5

   <=>3x+1=-9/10

   <=>3x=-9/10-1

   <=>3x=-19/10

   <=>x=-19/10:3

   <=>x=-19/30

   b)4-3/4(2x+1)^3=38/9

   <=>3/4(2x+1)^3=4-38/9

   <=>3/4(2x+1)^3=-2/9

   <=>(2x+1)^3=-2/9:3/4

   <=>(2x+1)^3=-8/27

   <=>(2x+1)^3=(-2/3)^3

   <=>2x+1=-2/3

   <=>2x=-2/3-1

   <=>2x=-5/3

   <=>x=-5/6

   Vậy x=-5/6

   Trả lời
2. Giải đáp:

    a)

   2.(3x+1)+1/2. 3/5=-3/2

   =>2.(3x+1)+ 3/10=-3/2

   =>2.(3x+1)=-3/2-3/10

   =>2.(3x+1)=-15/10-3/10

   =>2.(3x+1)=-18/10

   =>2.(3x+1)=-9/5

   =>3x+1=-9/5:2

   =>3x+1=-9/10

   =>3x=-9/10-1

   =>3x=-9/10-10/10

   =>3x=-19/10

   =>x=(-19/10):3

   =>x=-19/30

   Vậy x=-19/30

   ______________________

   b)

   4-3/4.(2x+1)^{3}=38/9

   =>3/4.(2x+1)^{3}=4-38/9

   =>3/4.(2x+1)^{3}=36/9-38/9

   =>3/4.(2x+1)^{3}=-2/9

   =>(2x+1)^{3}=(-2/9):3/4

   =>(2x+1)^{3}=(-8/27)

   =>(2x+1)^{3}=(-2/3)^{3}

   =>2x+1=-2/3

   =>2x=-2/3-1

   =>2x=-2/3-3/3

   =>2x=-5/3

   =>x=(-5/3):2

   =>x=-5/6

   Vậy x=-5/6

    

   Trả lời