`#Sad`
`a)`
`x^2-16 = 0`
`⇔ (x-4)(x+4) = 0`
`⇔` \(\left[ \begin{array}{l}x-4=0\\x+4=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\)
`\text{Vậy S=}` `{4; -4}`
`b)`
`9x^2-64 = 0`
`⇔ (3x)^2-8^2 = 0`
`⇔ (3x-8)(3x+8) = 0`
`⇔` \(\left[ \begin{array}{l}3x-8=0\\3x+8=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}3x=8\\3x=-8\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=\dfrac{8}{3}\\x=-\dfrac{8}{3}\end{array} \right.\)
`\text{Vậy S=}` `{8/3; -(8)/(3)}`
`c)`
`4x^2+4x+1 = 0`
`⇔ (2x)^2+2. 2x. 1+1^2 = 0`
`⇔ (2x+1)^2 = 0`
`⇔ 2x+1 = 0`
`⇔ 2x = -1`
`⇔ x = -(1)/2`
`\text{Vậy S=}` `{-1/2}`
`d)`
`(2x-1)^2-(4x^2-1) = 0`
`⇔ (2x-1)^2-(2x-1)(2x+1) = 0`
`⇔ (2x-1)(2x-1-2x-1) = 0`
`⇔ -2(2x-1) = 0`
`⇔ 2x-1 = 0`
`⇔ 2x = 1`
`⇔ x = 1/2`
`\text{Vậy S=}` `{1/2}`
`e)`
`(2x-1)^2-(x-3)^2 = 0`
`⇔ (2x-1-x+3)(2x-1+x-3) = 0`
`⇔ (x+2)(3x-4) = 0`
`⇔` \(\left[ \begin{array}{l}x+2=0\\3x-4=0\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-2\\3x=4\end{array} \right.\)
`⇔` \(\left[ \begin{array}{l}x=-2\\x=\dfrac{4}{3}\end{array} \right.\)
`\text{Vậy S=}` `{-2; 4/3}`
`f)`
`4(2+3x)(3x-2)-(6x+1)^2 = 7`
`⇔ 4(9x^2-4)-36x^2-12x-1-7 = 0`
`⇔ 36x^2-16-36x^2-12x-8 = 0`
`⇔ -12x-24 = 0`
`⇔ -12x = 24`
`⇔ x = -2`
`\text{Vậy S=}` `{-2}`
`g)`
`3(2x-1)^2-6x(2x-3) = 6`
`⇔ 3(4x^2-4x+1)-12x^2+18x-6 = 0`
`⇔ 12x^2-12x+3-12x^2+18x-6 = 0`
`⇔ 6x-3 = 0`
`⇔ 6x = 3`
`⇔ x = 1/2`
`\text{Vậy S=}` `{1/2}`