1) `123 - 5(x+4) = 38`
`-5(x+4) = -85`
`x+4 = 17`
`x=13`
2) `( 2 4/5 . x + 50): 2/3 = -51`
`2 4/5 . x + 50 = -34`
`2 4/5 .x = -84`
`x = -30`
3) `(3x-2^4).7^10 = 2. 7^11`
`3x . 7^10 - 2^4 . 7^10 = 2. 7^11`
`2x . 7^10 = 2 . 3 . 5. 7^10`
`2x = 2. 15`
`x=15`
4) `| 3/4 x - 1/2| = 1/4`
TH1:
`3/4 x - 1/2 = 1/4`
`3/4 x = 3/4`
`x = 1`
TH2 :
`3/4 x - 1/2 = -1/4`
`3/4 x = 1/4`
`x= 1/3`
Vậy `x=3/4 ; x=1/3`
