Question

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

Answer 1

Ответ:

1 (a - 2)( - 1) - a(a + 1) =

a^2 - 2a - a + 2 - a^2 - a =

-4a + 2

2) (b - 5)(b +10) + (b + 6)(b - 8) =

b^2 - 5b +10b - 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 + 14c - 14c - 49 =

2c^2 + 23

4) (3d + 5)(5d - 1) - (6d - 3)(2 - 8d) =

15d^2 - 3d + 25d - 5 - (12d - 6 - 48d + 24) =

15d^2 + 10d - 5 + 36d - 18 + 48d - 24 =

15d^2 + 94d - 47