1)
а) -5x (x-2) + (x-3) (5x+1)
= -5х² + 10х + 5х² - 15х + х - 3 = - 5х - 3
б) 3a ( a-b) - (a+b) (3a-b)
= 3a² - 3ab - (3a² + 3ab - ab - b²) =
= 3a² - 3ab - 3a² - 3ab + ab + b² = b² - 5ab
в) (2a-b) (3a+b) + (3a-5b) (a-b)
= 6a² - 3ab + 2ab - b² + 3a² - 5ab - 3ab + 5b² =
= 9a² - 9ab + 4b²
г) (5x²y - y) (x-2y) - (x² + 2y) (5x-3y)
=
= 5x³y - xy - 10x²y² + 2y³ - (5x³ + 10xy - 3x²y - 6y³) =
= 5x³y - xy - 10x²y² + 2y³ - 5x³ - 10xy + 3x²y + 6y³ =
= 5x³y - 10x²y² - 5x³ + 8y³ + 3x²y - 11xy
2)
а) 3a (a+3) + (2-a) (3a-4) =
3a² + 9a + 6a - 3a² - 8 + 4a = 19a - 8
б) 7x (x-2y) - (x-y) (7x+y)
= 7x² - 14xy - (7x² - 7xy + xy - y²) =
= 7x² - 14xy - 7x² + 7xy - xy + y² = y² - 8xy
в) (3m-2n) (2m-3n) + (3n-m) (2n-m)
=
= 6m² - 4mn - 9mn + 6n² + 6n² - 2mn - 3mn + m² =
= 7m² - 18mn + 12n²
г) (2a-5b²) (a+b) - (b²-2a) (a-5b) =
= 2a² - 5ab² + 2ab - 5b³ - (ab² - 2a² - 5b³ + 10ab) =
= 2a² - 5ab² + 2ab - 5b³ - ab² + 2a² + 5b³ - 10ab =
= - 6ab² + 4a² - 8ab