The triangle on the right is a scaled copy of the triangle on the left. Identify the scale factor. Express your answer as a whole number or fraction in simplest form.
20
20/3
A A
20/3
20

The transformation from f(x) to g(x) using

g(x)=a*f(x-h)+k

will stretch f(x) by a scale factor of a (>0), translates to the right by h, and translates upwards of k.

Similarly, the transformation from f(x) to g(x) using

g(x)=-a*f(x-h)+k

will stretch f(x) by a scale factor of a (>0) AND reflects over the x-axis, translates to the right by h, and finally translates upwards of k.

For the given problem,

f(x)=log_3(x)

a=-2  (dilates with scale factor of 2, AND with reflection over the x-axis)

h=0 (no horizontal translation)

k=3 (translates UPwards by 3 units)

Put into the above formula,

g(x)=-2f(x)+3=-2log_3(x)+3.

Note: in case you are not familiar with it, _ means subscript, and ^ means superscript, applicable to some text processing software.