Question

$(x-3) ^{3} +(y+1) ^{3}$

Answer 1

Se foloseste mai intai formula:
[tex]a^3+b^3=(a+b)(a^2-ab+b^2) \ si\ se \ obtine: [/tex]

$...=(x-3+y+1)[(x-3)^2-(x-3)(y+1)+(y+1)^2]=$

$=(x+y-2)(x^2+y^2-xy-7x+5y+13)$

Am folosit si formulele $(a\pm b)^2=a^2\pm 2ab+b^2$