\(\Leftrightarrow\left(4-3x\right)\left(4+3x\right)=0\)
=>x=4/3 hoặc x=-4/3
`16-9x^2 = 0`
`9x^2=16`
`x^2=16 : 9`
`x^2 =16/9`
`=>` \(x=\sqrt{\dfrac{16}{9}}\)
`x=4/3` hoặc `x=-4/3`
Vậy `S = {4/3; -4/3}`
9x2 = 16
x2 = 16/9
x2 = (4/3)2
x = \(\pm\) 4/3
=> x ∈ {4/3 ; -4/3}