║x+3/4 ║-3/4=1/3 2 mũ 3x+2=4x+5 (3x-5/12)mũ 2-121/64=0

a)

`|x+3/4|-3/4=1/3`

Với `x+3/4<0` hay `x<-3/4` thì `|x+3/4|=-x-3/4`

`→-x-3/4-3/4=1/3`

`→-x-3/2=1/3`

`→-x=1/3+3/2`

`→-x=11/6`

`→x=-11/6` (Thỏa mãn)

Với `x+3/4≥0` hay `x≥-3/4` thì `|x+3/4|=x+3/4`

`→x+3/4-3/4=1/3`

`→x=1/3` (Thỏa mãn)

Vậy `x∈{-11/6;1/3}`

b)

`2^3x+2=4x+5`

`→8x+2=4x+5`

`→4x=3`

`→x=3/4`

Vậy `x=3/4`

c)

`(3x-5/12)^2-121/64=0`

`→(3x-5/12)^2=121/64`

`→`\(\left[ \begin{array}{l}3x-\dfrac{5}{12}=\dfrac{11}{8}\\3x-\dfrac{5}{12}=\dfrac{-11}{8}\end{array} \right.\) 

`→`\(\left[ \begin{array}{l}3x=\dfrac{43}{24}\\3x=\dfrac{-23}{24}\end{array} \right.\) 

`→`\(\left[ \begin{array}{l}x=\dfrac{43}{72}\\x=\dfrac{-23}{72}\end{array} \right.\) 

Vậy `x∈{43/72;-23/72}`