So (1) is the slope range from point to point on the graph (5, 10).

These two values are obtained when the tangent position is (-5,0).

The range is 1/3 and 4/3.

(2) (-3,2) is within the circle X 2+Y 2 = 25, so the intersection of the straight line between (-3,2) and the origin (the center of X 2+Y 2 = 25) and the known graph is the largest, that is, the root number is 13+5.

(3) let x+y-3 = k.

y=-x+k+3

Therefore, y=-x and other straight lines are translated up and down, and it is found that there is a minimum value k+3=-5 root number 2 when tangent.

So the radical number of k=-5 is 2-3.

If you still don't understand, you can contact me directly After all, the process is quite long.