Question

ex 14 punctele a , b si d

Answer 1

$a) - 2xy(x + 3y) + 4x(xy - {y}^{2} )$

$= - 2 {x}^{2} y - 6x {y}^{2} + 4 {x}^{2} y - 4x {y}^{2}$

$= 2 {x}^{2} y - 10x {y}^{2}$

$= 2xy(x - 5y)$

$b)5x(x - 3) - 4x(2x - 3) + 3x(x + 1)$

$= 5 {x}^{2} - 15x - 8 {x}^{2} + 12x + 3 {x}^{2} + 3x$

$= 0$

$d)(x + 4)(x - 3) - (x - 1)(x + 6)$

$= {x}^{2} - 3x + 4x - 12 - {x}^{2} - 6x + x + 6$

$= -4x - 6$

$= 2(-2x - 3)$