Question

Tìm x thuộc N biết

3(x-9)+15=12+243:3²

1170:(x-13)=339-3.10²

Answer 1

\(3(x-9)+15=12+243:3^2\)

=> 3x - 27 + 15 = 12 + 243 : 9

=> 3x - 27 + 15 = 12 + 27

=> 3x - 27 + 15 = 39

=> 3x - 27 = 39 - 15

=> 3x - 27 = 24

=> 3x = 24 + 27

=> 3x = 51

=> x = 51 : 3 = 17

Vậy x = 17

\(1170:(x-13)=339-3\cdot10^2\)

=> 1170 : [x-13] = 339 - 3 . 100

=> 1170 : [x - 13] = 339 - 300

=> 1170 : [x-13] = 39

=> x - 13 = 30

=> x = 43

Answer 2

a) 3 ( x - 9 ) + 15 = 12 + 243 : 3²

3 ( x - 9 ) + 15 = 12 + 27

3 ( x - 9 ) + 15 = 39

3 ( x - 9 ) = 39 - 15

3 ( x - 9 ) = 24

x - 9 = 24 : 3

x - 9 = 8

x = 8 + 9

x = 17

Vậy x = 17

b) 1170 : ( x - 13 ) = 339 - 3 . 10²

1170 : ( x - 13 ) = 339 - 300

1170 : ( x - 13 ) = 39

x - 13 = 1170 : 39

x - 13 = 30

x = 30 + 13

x = 43

Vậy x = 43

=))

Answer 3

3.(x-9)+15=12+243:\(3^2\)

3.(x-9)+15=12+243:9

3.(x-9)+15=12+27

3.(x-9)+15=39

3.(x-9)=24

x-9=24:3

x-9=8

x=17

Vậy x=17

1170:(x-13)=339-3.\(10^2\)

1170:(x-13)=339-3.100

1170:(x-13)=339-300

1170:(x-13)=39

x-13=1170:39

x-13=30

x=30+13=43

Vậy x=43