Упростите: а) (12x^2 - 7xy - 9y^2) - (5xy - 17y^2 + 9x^2) б) 7x(x-y) - 3y(x+y) - 2x(2x -...

Question

Упростите: а) (12x^2 - 7xy - 9y^2) - (5xy - 17y^2 + 9x^2) б) 7x(x-y) - 3y(x+y) - 2x(2x - 3y)

Answer 1

а) (12х^2-7xy-9y^2)-(5xy-17y^2+9x^2)

12x^2-7xy-9y^2-5xy=17y^2-9x^2

3x^2-12xy+8y^2

б)7x(x-y)-3y(x+y)-2x(2x-3y)

7x^2-7xy-3xy-3y^2-4x^2+6xy

3x^2-4xy-3y^2