Answer:
The transformation from f to g represent by the horizontal stretch .
Step-by-step explanation:
Given  : f(x)=√(x)   and g(x)=√(0.4x).
To find : The transformation from f to g represents a __________ stretch.
Solution : We have given Parent function f(x)=√(x) .
By the transformation rule : f(x) →→ f(ax) .when  0<a<1.
Then it stretch horizontally by factor  .
.
Here we can compare the function  f(x)=√(x) →→ g(x)=√(0.4x).
Here, a = 0.4 ; 0 < 0.4< 1.
So, The transformation from f to g represent by the horizontal stretch .
Therefore,  the transformation from f to g represent by the horizontal stretch .