Question

1) Tìm x :

x + 125 - 45 + ( 12 + 23 ) = 155

x * 12 = ( 45 + 45 )

Answer 1

a)  x + 125 - 45 + (12+23) = 40

=>   x + 125 - 45 + 35 = 40

=>   x + 115 = 40

=>   x = 40 - 115

=>   x = -75

b) x * 12 = (45 + 45)

=>   x * 12 = 90

=>   x = 90 : 12

=>   x = 7,5

Answer 2

x + 125 - 45 + ( 12 + 23 ) = 40

=> x + 125 +( -45) + 35 = 40

=> x + 80 +35 = 40

=> x + 115 = 40

=> x = -75

x * 12 = ( 45 + 45 )

=> x * 12 = 90 

=> x = 90 : 12 

=> x = 15/2 = 7.5

Answer 3

a) x + 125 - 45 + (12 + 23) = 40

   x + 125 - 45 + 35          = 40

   x                                 = 40 - 35 + 45 - 125

   x                                 = - 65

b) x * 12 = 45 + 45

    x * 12 = 90

    x        = 90 : 12

    x        = 7,5