tìm số tự nhiên x biết : a) 3x + 2x = 6² – 2^0 b)5x + x= 120 : 2 c)6x + x = 5^11 : 5^9 + 3^1 d)4x + 2x = 68 – 2^19 : 2^16 giú

2 bình luận về “tìm số tự nhiên x biết : a) 3x + 2x = 6² – 2^0 b)5x + x= 120 : 2 c)6x + x = 5^11 : 5^9 + 3^1 d)4x + 2x = 68 – 2^19 : 2^16 giú”

1. a) 3x + 2x = 6^2 – 2^0

   => ( 3 + 2 ) . x = 36 – 1

   => 5 . x = 35

   => x = 35 : 5

   => x = 7

   Vậy x = 7 .

   b) 5x + x = 120 : 2

   => ( 5 + 1 ) . x = 120 : 2

   => 6 . x = 60

   => x = 60 : 6

   => x = 10

   Vậy x = 10 .

   c) 6x + x = 5^11 : 5^9 + 3^1

   => ( 6 + 1 ) . x = 5^(11-9) + 3

   => 7 . x = 5^2 + 3

   => 7 . x = 25 + 3

   => 7 . x = 28

   => x = 28 : 7

   => x = 4

   Vậy x = 4 .

   d) 4x + 2x = 68 – 2^19 : 2^16

   => ( 4 + 2 ) . x = 68 – 2^(19-16)

   => 6 . x = 68 – 2^3

   => 6 . x = 68 – 8

   => 6 . x = 60

   => x = 60 : 6

   => x = 10

   Vậy x = 10 .

   Trả lời
2. #Chanhh

   a) 3x + 2x = 6^2 – 2^0

   => ( 3 + 2 ) x = 36 – 1

   => 5x = 35

   => x = 35/5

   => x = 7

   __

   b) 5x + x = 120/2

   => 5x + 1x = 60

   => ( 5 + 1 )x = 60

   => 6x = 60

   => x = 60/6

   => x = 10

   __

   c) 6x + x = 5^11 : 5^9 + 3^1

   => 6x + 1x = 5^2 + 3

   => ( 6 + 1 ) x = 25 + 3

   => 7x = 28

   => x = 28/7

   => x = 4

   __

   d) 4x + 2x = 68 – 2^19 : 2^16

   => ( 4 + 2 ) x = 68 – 2^3

   => 6x = 68 – 8

   => 6x = 60

   => x = 60/6

   => x = 10

   Trả lời