7=xy= 1*7=7*1=(-7)*(-1)=(-1)*(-7)
x=1. y=7
x=7, y=1
x=-1, y=-7
x=-7, y=-1
12=(x-1)(y+2)= 1*12=(-1)*(-12)=2*6 =(-2)*(-6)=3*4=(-3)*(-4)=4*3=(-4)*(-3)=6*2=(-6)*(-2)=12*1=(-12)*(-1)
vom avea 12 solutii, 12v perechi x, y determinate astfel
x-1=1...x=2
y+2=12...y=10
x-1=-1...x=0
y+2=-12...y=-14
..........................
...........................
x-1=-12...x=-11
y+2=-1....y=-3
