D. None of these.
Equilateral is the only triangle that has all the sides that are equal to each other. Hope this helped you :)
NO!!!!!!! 1450/7 is correct because 6x+x=1456 7x=1456 x=208
If function and inverse be

Both will seem to be opposite and similar .
Look at the first one
It is showing like 1 is function and other one is its inverse(Attachment )
Hence 1st one is the answer