Question

Вычислите (31.18--31.19)​

Answer 1

Відповідь:

$\frac{38^{2}-28^{2} }{47^{2}-19^{2}} =\frac{2^{2}*19^{2}-2^{2}*14^{2}}{47^{2}-19^{2}} =\frac{2^{2}(19^{2}-14^{2})}{47^{2}-19^{2}} =\frac{4*165}{2209-361} =660:1848=\frac{165}{462}$

$\frac{53^{2}-25^{2}}{79^{2}-51^{2}} =\frac{2809-625}{6241-2601} =\frac{2184}{3640} =\frac{273}{455} =0,6$

$\frac{181^{2}-61^{2}}{319^{2}-77^{2}} =\frac{32761-3721}{101761-5929} =\frac{29040}{95832} =\frac{3630}{11979}$

$\frac{200^{2}-380^{2}}{420^{2}-160^{2}} =\frac{40000-144400}{176400-25600} =\frac{-104400}{150800} =\frac{-1044}{1508} =-\frac{261}{377}$