Answer:-1 I think(Once simplified)
Step-by-step explanation: Let's look at the down left vertice of the isosceles triangle
Slope over the line: To reach the dot over the line you will have to go down three, right three from the second quadrant making that -1 simplified. To reach the dotted line from quadrant 4 up three, three left making that -1 as well.
Now for the vertices itself...
The vertice in Q2 is at coordinate (-2,6) and the coordinate in Q4 is (4,0).To go from the coordinate in q2 to the vertice in q4, you go down 6, right 6. To go from the vertice in q4 you have to up 6, left 6. Once simplified from the slope of the translation of coordinates after their shift in position from the reflection it will also lead to a final rendition of -1 as well.
Sorry it took so much space, Please let me know what the automated explanation and/or an answer is. Hope this helps or helped!!