b) (x+2)5=210 c) 5x : 52 = 125 d) (3x-24) . 73= 2x74 ( câu a khá dài nên mình để sau nhé )
(x+2)5=45 5x : 52 = 53 (3x-24) . 73= 2x74 : 73
x+2=4 5x = 53 . 52 3x-24 = 2x7
x=4-2 5x = 55 3x -16 =14
x=2 x = 5 3x=14+16
3x=30
x=30:3
x=10
a) (x-5)4 = (x-5)6
(x-5)4 - (x-5)6 =0
(x-5)4 - (x-5)4 . (x-5)2 =0
(x-5)4 - [ 1- (x-5 )2 ] =0
TH1: ( x-5 )4 =0 TH2: 1-( x-5)2 = 0
x-5=0 (x-5)2 = 1-0
x=0+5 (x-5)2 =1
x=5 x-5 = +-1
* x-5=1
x=6
* x-5=-1
x=4