Упр.33.34 ГДЗ Мордкович 7 класс (Алгебра)

1. $$2+(3a-b)^2$$
2. $$9p^2-(q-3p)^2$$
3. $$(5c+7d)^2-70cd$$
4. $$(8m-n)^2-64m^2$$

1. $$a^2+(3a-b)^2=a^2+9a^2-6ab+b^2=10a^2-6ab+b^2.$$

2. $$9p^2-(q-3p)^2=9p^2-q^2+6pq-9p^2=-q^2+6pq.$$

3. $$(5c+7d)^2-70cd=25c^2+70cd+49d^2-70cd=25c^2+49d^2.$$

4. $$(8m-n)^2-64m^2=64m^2-16mn+n^2-64m^2=n^2-16mn.$$

Ответ

а) $$10a^2-6ab+b^2$$; б) $$-q^2+6pq$$; в) $$25c^2+49d^2$$; г) $$n^2-16mn$$.