Tìm X: a) 75 x  (x + 157)

a) 75 $\times$ (x + 157) = 24 450 + 21 000

    75 $\times$ (x + 157) = 45 450

              x + 157  = 45 450 : 75

              x + 157  = 606

              x            = 606 – 157

              x            = 449

b) 14 700 : (x + 47) = 84 – 35

     14 700 : (x + 47) = 49

                    x + 47 = 14 700 : 49

                    x + 47 = 300

                    x          = 300 – 47

                    x          = 253

c) 69 $\times$ (x – 157) = 18 837 + 24 564

    69 $\times$ (x – 157) = 43 401

              x – 157 = 43 401 : 69

              x – 157 = 629

              x           = 629 + 157

              x           = 786

d) 41 829 : (x – 384) = 98 – 25

     41 829 : (x – 384) = 73

                      x – 384 = 41 829 : 73

                      x – 384 = 573

                      x           = 573 + 384

x= 957