Question

Tìm x :

a/ ( x + 6 )⁴ - ( x + 6 )⁶ =0

b/ | x + 3 | . ( x - 7 ) < 0

Answer 1

Answer 2

a,(x+6)^4-(x+6)^6=0

<=>(x+6)^4-(x+6)^4.(x+6)^2=0

<=>(x+6)^4.[1-(x+6)^2]=0

TH1:(x+6)^4=0=>x+6=0=>x=-6

TH2:1-(x+6)^2=0=>(x+6)^2=1=>x+6=1 hoặc x+6=-1

=>x=-5 hoặc x=-7

 Vậy x E {-7;-6;-5}

Tick nhé

Answer 3

a,(x+6)^4-(x+6)^6=0

<=>(x+6)^4-(x+6)^4.(x+6)^2=0

<=>(x+6)^4.[1-(x+6)^2]=0

TH1:(x+6)^4=0=>x+6=0=>x=-6

TH2:1-(x+6)^2=0=>(x+6)^2=1=>x+6=1 hoặc x+6=-1

=>x=-5 hoặc x=-7

Vậy x E {-7;-6;-5}