Вычислите:200^2-60^2\420^2-160^2

[latex] \frac{ 200^{2}-60^{2} }{ 420^{2}-160^{2} } = \frac{ 140^{2}}{ 260^{2}} = \frac{ 7^{2}}{13^{2}} = \frac{49}{169} [/latex]