me translate yer gibberish talk tu meen: . . . yu want a strate line thru 2 points: (0.3,0.7) & (0.7, 0.5) . . . deltax=0.7 -0.3=0.4 . . . deltay=0.5 -0.7=-0.2 . . . slope=deltay/deltay=-2/4=-0.5 . . . y=-0.5x+konst . . . projekt line from x=0.3 tu x=0.....deltax=-0.3 . . . deltay=slope*deltax=(-0.5)*(-0.3)=+0.15 . . . y at x=0...0.7 +0.15=0.85 . . . y=-0.5x +0.85