me assume yu want strate line thru 2 points: (-2,-9) & (2,4)
deltax=2-(-2)=4
deltay=4-(-9)=+13
slope=deltay/deltax=13/4=3.25
y=3.25x+konst
projekt line from=-2 tu x=0...deltax=+2, so deltay=slope*deltax=3.25*2=6.5
thus, y at x=0 must be -9+6.5=-2.5
y=3.25x-2.5