Toán Lớp 6: TÌM X 70-5(X-3)=45 144:(2X-138)=2MŨ3.3MŨ2 450:(X-19)=50 71-(33+X)=26 140+2.(X-3)=150

Question

Toán Lớp 6:  TÌM X 70-5(X-3)=45 144:(2X-138)=2MŨ3.3MŨ2 450:(X-19)=50 71-(33+X)=26 140+2.(X-3)=150

hiennhi98 · Answer

$ text{a)70 - 5 . (x - 3) = 45}$   $ text{&rArr; 5 . (x - 3) = 70 - 45}$   $ text{&rArr; 5 . (x - 3) = 25}$   $ text{&rArr; x - 3        = 25 &divide; 5}$   $ text{&rArr; x - 3        = 5}$   $ text{&rArr; x              = 5 + 3}$   $ text{&rArr; x              = 8}$   $ text{b)144 &divide; (2x - 138) = 2&sup3; . 3&sup2;}$   $ text{&rArr;144 &divide; (2x - 138) = 72}$   $ text{&rArr;2x - 138              = 144 &divide; 72}$   $ text{&rArr;2x - 138              = 2}$   $ text{&rArr;2x                        = 2 + 138}$   $ text{&rArr;2x                        = 140}$   $ text{&rArr;x                          = 70}$   $ text{c)450 &divide; (x - 19) = 50}$   $ text{&rArr; x - 19            = 450 &divide; 50}$   $ text{&rArr; x - 19            = 9}$   $ text{&rArr; x                    = 9 + 19}$   $ text{&rArr; x                    = 28}$

cobelolen · Answer

$ text{a)70 - 5 . (x - 3) = 45}$   $ text{&rArr; 5 . (x - 3) = 70 - 45}$   $ text{&rArr; 5 . (x - 3) = 25}$   $ text{&rArr; x - 3        = 25 &divide; 5}$   $ text{&rArr; x - 3        = 5}$   $ text{&rArr; x              = 5 + 3}$   $ text{&rArr; x              = 8}$   $ text{b)144 &divide; (2x - 138) = 2&sup3; . 3&sup2;}$   $ text{&rArr;144 &divide; (2x - 138) = 72}$   $ text{&rArr;2x - 138              = 144 &divide; 72}$   $ text{&rArr;2x - 138              = 2}$   $ text{&rArr;2x                        = 2 + 138}$   $ text{&rArr;2x                        = 140}$   $ text{&rArr;x                          = 70}$   $ text{c)450 &divide; (x - 19) = 50}$   $ text{&rArr; x - 19            = 450 &divide; 50}$   $ text{&rArr; x - 19            = 9}$   $ text{&rArr; x                    = 9 + 19}$   $ text{&rArr; x                    = 28}$   $ text{d)71 - (33 + x) = 26}$   $ text{&rArr; 33 + x          = 71 - 26}$   $ text{&rArr; 33 + x          = 45}$   $ text{&rArr; x                  = 45 - 33}$   $ text{&rArr; x                  = 12}$   $ text{e)140 + 2 . (x - 3) = 150}$   $ text{&rArr; 2 . (x - 3)          = 150 - 140}$   $ text{&rArr; 2 . (x - 3)          = 10}$   $ text{&rArr; x - 3                 = 10 &divide; 2}$   $ text{&rArr; x - 3                 = 5}$   $ text{&rArr; x                       = 5 + 3}$   $ text{&rArr; x                       = 8}$