Question

Tìm x

a . ( 17x + 23 ) : 12 = 9

b . 345 - ( 15x + 63 ) = 102

c . ( 11x - 2³ ) . 7³ = 5 . 7⁵

Answer 1

a . ( 17x + 23 ) : 12 = 9

=> 17x + 23 = 9 x 12

=> 17x + 23 = 108

=> 17x = 108 - 23

=> 17x = 85

=> x = 5

Vậy x = 5

b . 345 - ( 15x + 63 ) = 102

=> 15x + 63 = 345 - 102

=> 15x + 63 = 243

=> 15x = 243 - 63

=> 15x = 180

=> x = 12

Vậy x = 12

c . ( 11x - 2³ ) . 7³ = 5 . 7⁵

=> ( 11x - 2³ ) . 7³ = 84035

=> ( 11x - 2³ ) . 343 = 84035

=>  11x - 8 = 84035 : 343

= > 11x - 8 = 245

=> 11x = 245 + 8

=> 11x = 253

=> x = 23

Vậy x = 23