Question

Tìm x biết : ( 7x - 11 )^3 = 2^5 . 5^2 + 200

Answer 1

( 7x - 11 )³ = 32 . 25 + 200

( 7x - 11 )³ = 800 + 200

( 7x - 11 )³ = 1000

( 7x - 11 )³ = 10³

=> 7x - 11 = 10

7x = 10 + 11

7x = 21

x = 21 : 7

x = 3

Answer 2

=>(7x-11)^3=800+200=1000=10^3

=>7x-11=10

=>7x=21=>x=3

 Vậy x=3