Question

Выражение: 1)(a-2)(a-1)-a(a+1) 2)(b-5)(b+10)+(b+6)(b-8) 3)(2c+3)(3c++7)(2c-7) 4)(3d+5)(5d--3)(2-8d)

Answer 1

Объяснение:

1)

$(a-2)(a-1) - a(a-1)= a^{2} -a-2a+2 -a^{2} -a=-4a+2;$

2)

$(b-5)(b+10)+(b+6)(b-8)=b^{2} +10b-5b-50+b^{2} -8b+6b-48=\\2b^{2} +3b-98;$

3)

$(2c+3)(3c+2) -(2c+7)(2c-7) =6c^{2} +4c+9c+6-4c^{2} +49=2c^{2} +13c+55;$

4)

$(3d+5)(5d-1)-(6d-3)(2-8d)= 15d^{2} -3d+25d-5-12d+48d^{2} +6-24d=\\63d^{2} -14d+1.$