Question

to tylko cztery przykłady z matmy 4x-5=23(x+2)=x-55/6 (x-6)=4x-32(x-5)=3(x+7)2-(x+7)=3x-5musza być sprawdzenia

Answer 1

1)    4x -5 = 2                                     Spr.        L = 4 · ⁷/₄ - 5 = 7 - 5 = 2

         4x = 7     /:4                                              P = 2

             x = ⁷/₄ = 1¾                                                        L = P

2)   3(x+2) = x -5

       3x + 6 = x - 5

       3x -x = -5 -6                                 Spr.     L = 3(-5½ + 2) = 3 · (-3½) = 3 · (-⁷/₂) = -²¹/₂ = -10½

          2x = -11      /:2                                       P = -5½ - 5 = -10½

            x = - ¹¹/₂ = - 5½                                              L = P

3)   ⁵/₆( x -6) = 4x -3

         ⁵/₆ x - 5 = 4x -3    /·6

        5x - 30 = 24x - 18                     Spr.   L =  ⅚(-¹²/₁₉ - 6) = -¹⁰/₁₉ - 5 = -5¹⁰/₁₉

        5x - 24x = -18 + 30                             P = 4· (-¹²/₁₉) -3 = -⁴⁸/₁₉ - 3 = -2¹₁₉ -3 = -5¹⁰/₁₉

        -19x = 12     /:(-19)                                   L = P

           x = - ¹²/₁₉

4)     2(x -5) = 3(x+7)

         2x -10 = 3x + 21                          Spr.   L = 2(-31 -5) = 2· (-36) = -72

         2x -3x = 21 +10                                     P = 3(-31 +7) = 3 · (-24) = -72

           -x = 31     /·(-1)                                                L = P

             x = -31

5)    2 - (x+7) = 3x -5

        2 -x -7 = 3x -5                                   Spr.   L = 2 - (0 +7) = 2 - 7 = - 5

          -x -3x = -5 +7 -2                                           P = 3 ·0  -5 = 0 -5 = -5

            -4x = 0        /:(-4)                                             L = P

              x = 0