Question

4. Вычислите: a) 35²-70-20+20² ​

Answer 1

$\displaystyle\bf\\35^{2} -70\cdot 20+20^{2} =35^{2} -2\cdot35\cdot 20+20^{2} =\\\\=(35-20)^{2} =15^{2} =225$