m = (y2-y1)/(x2-x1) so for your question (2--8)/(4--3) = (2+8)/(4+3) = 10/7
Now to find the slope-intercept form (y=mx+b) plug in the slope and a point to find b. I'm going to use point T. So 2 = (10/7)*4 +b => b = 2 - (40/7) = -26/7. So the answer would be y = (10/7)x - (26/7).
Hope this helps!
