Question

Calculati:

a) (x + 2) (x la 2 + 4x -3)

b) (x la 2 -xy +y la 2) (x - y +1)

Answer 1

a) ( x + 2 )( x² + 4x - 3 ) =

= x( x² + 4x - 3 ) + 2( x² + 4x - 3 ) = x³ + 4x² - 3x + 2x² + 8x - 6 =

= x³ + 6x² - 3x + 8x - 6 = x³ + 6x² + 5x - 6

b) ( x² - xy + y² )( x - y + 1 ) = x²( x - y + 1 ) - xy( x - y + 1 ) + y²(x - y + 1 ) =

= x³ - x²y + x² - x²y + xy² - xy + xy² - y³ + y² =

= x³ - 2x²y + x² + 2xy² - xy - y³ + y²