[tex]\bf -9(3x-2)^2=-225\implies (3x-2)^2=\cfrac{-225}{-9}\implies (3x-2)^2=\cfrac{225}{9}
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3x-2=\sqrt{\cfrac{225}{9}}\implies 3x-2=\cfrac{\sqrt{225}}{\sqrt{9}}\implies 3x-2=\cfrac{15}{3}
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3x=\cfrac{15}{3}+2\implies 3x=\cfrac{21}{3}\implies x=\cfrac{21}{9}[/tex]