If you were to round it, a possible answer could be 9,997
Before dilation:
the height of the triangle is h₁ = 7 - (-1) = 8
the width of the triangle is w₁ = 7 - (-5) = 12
After dilation:
the height of the is h₂ = 9-7 = 2
the width of the triangle is w₂ = -5 - (-8) = 3
The scale factor is h₂/h₁ = 2/8 = 1/4 = 0.25
Also, the scale factor is w₂/w₁ = 3/12 = 1/4 = 0.25
Answer: The scale factor is 0.25