Question

Tema R se consideră legea de compozitie
x*y=xy-3×-3y+12
a)calculati
2*(-1); 1*2; 0*(-3); 2*3
b)aratati ca
x*y=(×-3)(×-3)(y-3)+3
c)rezolvati ecuatia
x*×=3​

Answer 1

Răspuns:

a) 2*(-1) = 2×(-1)-3×2-3×(-1)+12=-2-6+3+12=11

1*2 = 1×2-3×1-3×2+12=2-3-6+12=5

0*(-3) = 0×(-3)-3×0-3×(-3)+12=21

2*3=2×3-3×2-3×3+12=6-6-9+12=3

b) x*y=xy-3x-3y+12

x*y= x(y-3)-3(y-3)+3

x*y= (y-3)(x-3)+3

x*y= (x-3)(y-3)+3

c) x*x=3 <=>

(x-3)(x-3)+3=3

(x-3)^2=3-3

(x-3)^2=0 <=> x-3=0 => x=3