Answer:
4
Explanation:
compare the coordinates of each point:
G: (1,2) x4→ G': (4,8)
H: (3,0) x4→ H': (12,0)
I: (2,-2) x4→ I': (8,-8)
As you can see the scale factor is 4
Each x and each y coordinate of the small triangle GHI is multiplied by 4 to get the image triangle G'H'I'