$@angela2206$
a) | x + 2 | = 2,25
-> x + 2 = ± 2,25
*TH1 : x + 2 = 2,25
x = 2,25 - 2
x = 0,25 .
*TH2 : x + 2 = - 2,25
x = - 2,25 - 2
x = - 4,25 .
Vậy : x = { 0,25 ; - 4,25 }
-------------------------------------------------------------------
b ) 1 - | x - $\frac{1}{2}$ | = $\frac{1}{2}$
| x - $\frac{1}{2}$ | = 1 - $\frac{1}{2}$
| x - $\frac{1}{2}$ | = $\frac{1}{2}$
-> x - $\frac{1}{2}$ = ± $\frac{1}{2}$
*TH1 : x - $\frac{1}{2}$ = $\frac{1}{2}$
x = $\frac{1}{2}$ + $\frac{1}{2}$
x = 1 .
*TH2 : x - $\frac{1}{2}$ = $\frac{-1}{2}$
x = $\frac{-1}{2}$ + $\frac{1}{2}$
x = 0 .
Vậy : x = { 1 ; 0 }
-------------------------------------------------------------------
c) 3.|x - 1| = 4 .
| x - 1 | = 4 : 3
| x - 1 | = - $\frac{4}{3}$
-> x - 1 = ± $\frac{4}{3}$
*TH1 : x - 1 = $\frac{4}{3}$ .
x = $\frac{4}{3}$ + 1
x = $\frac{7}{3}$
*TH2 : x - 1 = $\frac{-4}{3}$
x = $\frac{-4}{3}$ + 1
x = $\frac{-1}{3}$ .
Vậy : x = { $\frac{7}{3}$ ; $\frac{-1}{3}$ }
-------------------------------------------------------------------
d) |x| - 6 = 2 - |x|
|x| + |x| = 2 + 6 .
|x| x 2 = 8
|x| = 8 : 2 .
|x| = 4 .
-> x = ± 4 .
Vậy x = ± 4
#chucbanhoctotnha!!!
