Question

tìm x biết (x-5)⁴=(x-5)⁶

Answer 1

 

(x-5)⁴=(x-5)⁶ 

x⁴ - 625 = x⁶ - 15625

=> x⁶ - x⁴ = 15 000

=> x⁶ - x⁴ = 5⁶ - 5⁴

=> x = 5

Answer 2

đặt x-5=t

=>t⁴=t⁶

=>t⁶-t⁴=0

=>t⁴(t²-1)=0

=>t⁴(t-1)(t+1)=0

=>t=-1;0;1

=>x=4;5;6

vậy x=4;5;6