After giving 20% discount a fan is sold at Rs 12480 find its marked price

Quick translate "x is 12 units from 20" into an equation. what are the values of x being described? if you can answer any of my other questions that'd be great too

To prove that def ~ gfh by the sss similarity theorem using the information provided in the diagram, it would be enough additional information to know that

F(x) = x2 − 9, and g(x) = x − 3 f(x) = x2 − 4x + 3, and g(x) = x − 3 f(x) = x2 + 4x − 5, and g(x) = x − 1 f(x) = x2 − 16, and g(x) = x − 4 h(x) = x + 5 arrowright h(x) = x + 3 arrowright h(x) = x + 4 arrowright h(x) = x − 1 arrowright