Question

Tìm x biết : x * 7 +x * 9 - x - x * 5 = 790

Answer 1

x . 7 + x . 9 - x - x . 5 = 790

=> x . 7 + x . 9 - x . 1 - x . 5 = 790

=> x . (7 + 9 - 1 - 5) = 790

=> x . 10 = 790

=> x = 790 : 10

=> x = 79

Answer 2

x=79

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Answer 3

x * ( 7 + 9 - 1 - 5 ) =  790

x                     =  790 : 10

x                     =         79