strate line tween 2 points: (-5,-7) & (-2, -9)
deltax=+3, deltay=-2, slope=deltay/deltax=-2/3
line: y=(-2/3)x +konst
extend line from x=-2 tu x=0...deltax=2, deltay=slope*deltax=2*(-2/3)=-4/3
nu y=old y+deltay=-9 -4/3=-(10 & 1/3) or -31/3
y=(-2/3)x -31/3