Упр.10.3 ГДЗ Мерзляк Поляков 7 класс (Алгебра)

1) (5a^4+3a^2 b-b^3 )-(3a^4-4a^2 b-b^2 );
2) (12xy-10x^2+9y^2 )-(-14x^2+9xy-14y^2 );
3) (7ab^2-8ab+4a^2 b)+(10ab-7a^2 b);
4) (2c^2+3c)+(-c^2+c)-(c^2+4c-1).

1. $$\left(5a^4+3a^2b-b^3\right)-\left(3a^4-4a^2b-b^2\right)$$
   $$=5a^4+3a^2b-b^3-3a^4+4a^2b+b^2$$
   $$=2a^4+7a^2b-b^3+b^2.$$

2. $$\left(12xy-10x^2+9y^2\right)-\left(-14x^2+9xy-14y^2\right)$$
   $$=12xy-10x^2+9y^2+14x^2-9xy+14y^2$$
   $$=4x^2+3xy+23y^2.$$

3. $$\left(7ab^2-8ab+4a^2b\right)+\left(10ab-7a^2b\right)$$
   $$=7ab^2-8ab+4a^2b+10ab-7a^2b$$
   $$=7ab^2+2ab-3a^2b.$$

4. $$\left(2c^2+3c\right)+\left(-c^2+c\right)-\left(c^2+4c-1\right)$$
   $$=2c^2+3c-c^2+c-c^2-4c+1$$
   $$=1.$$

Ответ

1) $$2a^4+7a^2b-b^3+b^2$$
2) $$4x^2+3xy+23y^2$$
3) $$7ab^2+2ab-3a^2b$$
4) $$1$$