So subtract the Ys and subtract the Xs , then divide the answer you got for y over the answer you got for x. -3-t/10-9= -7, that simplifies to -3-t/1=-7 or -3-t=-7, from there you can add 3 to both sides to get -t=-4, which is the same as t=4. Plug it in to see if it’s makes sense . Hope this helps ; )