[tex]\bf \cfrac{3t^2}{5}-\cfrac{4t^2}{15}\impliedby \stackrel{LCD}{15}\implies \cfrac{3t^2(3)-4t^2(1)}{15}\implies \cfrac{9t^2-4t^2}{15}\implies \cfrac{5t^2}{15}
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\cfrac{5}{15}\cdot t^2 \implies \cfrac{1}{3}\cdot t^2\implies \cfrac{t^2}{3}[/tex]