Question

Fie (R , steluță ) , x steluta y = xy+3x+3y+6 .

Va rog dau coroana punctul c in poza ​

Answer 1

Explicație pas cu pas:

b)

x¤y = xy+3x+3y+6

y¤x = yx+3y+3x+6

x¤y = y¤x => grup comutativ

c)

x¤y = xy+3x+3y+6 = (x+3)(y+3) - 3

$C_{n}^{2} \circ C_{n}^{2} = 13$

$(C_{n}^{2} + 3)^{2} - 3 = 13 \iff (C_{n}^{2} + 3)^{2} = 16$

$|C_{n}^{2} + 3| = 4 \iff C_{n}^{2} + 3 = \pm 4$

$C_{n}^{2} > 0 \implies C_{n}^{2} = 1$

$\dfrac{n!}{2!(n-2)!} = 1 \iff \dfrac{(n - 2)!(n - 1)n}{2(n-2)!} = 1$

$n(n - 1) = 2 \iff {n}^{2} - n - 2 = 0$

$(n + 1)(n - 2) = 0$

$n \geqslant 0 \implies \bf n = 2$

Answer 2

Răspuns:

Explicație pas cu pas: