Đáp án :
$\frac{3x +1}{15}$+1$\frac{2}{3}$ = $\frac{15x}{25}$ - 1
$\frac{3x +1}{15}$+ $\frac{5}{3}$ = $\frac{15x}{25}$ - 1
$\frac{15x +5}{75}$+ $\frac{125}{75}$ = $\frac{45x}{75}$ - $\frac{75}{75}$
15x + 5 + 125 = 45x - 75
15x + 130 = 45x - 75
75 + 130 = 45x - 15x
205 = 30x
⇒ x = 205 : 30 = $\frac{41}{6}$
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