NOW AGAIN WITH PICTURE THIS TIME MATH PROBLEMS 2 PLS HELP HOPE NOT TO SMALL BUT TRY THE ZOOM THAT MIGHT MAKE IT MORE VISIBLE IF TOO SMALL LET ME KNOW

Which of the following expressions are equivalent ?

We just started the introduction into circles and i have no idea how to do this.

How many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.) how many 3-digit numbers can you write using only digits 1 and 7? (of course, digits can repeat.)