Question

10. Simplify (3x – y) (3x + y + y2) – (2x + 3y) (x2 + x - 1).​

Answer 1

Answer:

7x² +3xy² - y² - y³ - 2x³ + 2x - 3yx² - 3yx + 3y

Step-by-step explanation:

$(3x-y)(3x+y+y^2) - (2x+3y)(x^2+x-1)\\= [3x(3x+y+y^2)-y(3x+y+y^2)]-[2x(x^2+x-1)+3y(x^2+x-1)]\\= [9x^2 + 3xy + 3xy^2 - 3xy - y^2 -y^3] - [2x^3 + 2x^2 - 2x + 3yx^2 + 3yx -3y]\\= 9x^2 +3xy^2 - y^2 - y^3 - 2x^3 - 2x^2 + 2x - 3yx^2 - 3yx + 3y\\= 7x^2 +3xy^2 - y^2 - y^3 - 2x^3 + 2x - 3yx^2 - 3yx + 3y$