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thienthanlove20

[TEX]\frac{2a - b}{3a - b} + \frac{5b - a}{3a + b}[/TEX]

[TEX]= \frac{3a^2 - 6b^2 + 15ab}{9a^2 - b^2}[/TEX]

[TEX]= \frac{3(a^2 - 2b^2 + 5ab)}{9a^2 - b^2}[/TEX]

[TEX]= \frac{3(10a^2 - 3b^2 + 5ab - 9a^2 + b^2)}{9a^2 - b^2}[/TEX]

[TEX]= \frac{3(9a^2 - b^2)}{9a^2 - b^2}[/TEX]

[TEX]= 3[/TEX]
 
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