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
