Toán Lớp 7: Tìm x a, -5/4-x=-1/4. B,-2/3+(x+1/2)=-5/3. C,(-3/4-x)-2/3=-1/3. D, 1/2 :x +-3/4=-5/4. E, -4/3 +1/3×(x-3/2)=2/3.

Question

Toán Lớp 7:  Tìm x         a, -5/4-x=-1/4.    B,-2/3+(x+1/2)=-5/3.      C,(-3/4-x)-2/3=-1/3.    D, 1/2 :x +-3/4=-5/4.   E, -4/3 +1/3×(x-3/2)=2/3.         MK ĐANG CẦN GẤP ,MONG MN GIÚP MK

tonhitruc · Answer

a) -5/4 - x = -1/4                x = -5/4 - (-1/4)                 x = -1   ------------------------------------   b) -2/3 + (x + 1/2) = -5/3                    ( x + 1/2) = -5/3 - (-2/3)                      x+ 1/2 = -1                      x          = -1 - 1/2                      x          = -3/2    -------------------------------------------------------------------   c) (-3/4 - x) - 2/3 = -1/3         ( -3/4 - x)       = -1/3 + 2/3         -3/4 - x          = 1/3                   x          =-3/4 - 1/3                     x      =-13/12   ----------------------------------------------------------   d) 1/2 : x +  frac{-3}{4} = -5/4    1/2 : x                          = -5/4 -  frac{-3}{4}    1/2 : x                           = -1/2             x                         = 1/2 : (-1/2)              x                        =-1   -------------------------------------------------------------   e) -4/3 + 1/3 . ( x - 3/2) = 2/3                    1/3 . ( x - 3/2)= 2/3 - (-4/3)                     1/3 . ( x - 3/2)= 2                             ( x - 3/2) = 2 : 1/3                             x - 3/2 = 6                              x       = 6 + 3/2                              x       = 15/2

thudan · Answer

Giải đáp + Lời giải và giải thích chi tiết:   a, -5/4-x=-1/4   &hArr; -x = -1/4 + 5/4   &hArr; -x = 4/4   &hArr; x = -4/4   Vậy x = -4/4   b, -2/3+(x+1/2)=-5/3   &hArr; x + 1/2 = -5/3 + -2/3   &hArr; x + 1/2 = -3/3   &hArr; x = -3/3 - 1/2   &hArr; x = -3/2   Vậy x = -3/2   c, (-3/4-x)-2/3=-1/3   &hArr; -3/4-x = -1/3 + 2/3   &hArr; -3/4-x = 1/3   &hArr; -x = 13/12   &hArr; x = -13/12   Vậy x = -3/12   d, 1/2 : x + (-3/4) = -5/4   ĐKXĐ : x  ne 0   &hArr; 1 : 2x + (-3/4) = -5/4   &hArr; 2/(4x) + ((-3x)/(4x)) = (-5x)/(4x)   &hArr; 2 - 3x = - 5x   &hArr; -3x = -5x - 2   &hArr; 2x = -2   <=> x = -1(TM)   Vậy x = 1   e, -4/3 + 1/3(x-3/2)=2/3   &hArr; 1/3(x-3/2) = 2   &hArr; x - 3/2 = 6   &hArr; x = 15/2   Vậy x = 15/2