How do you rewrite 6^6*6^-2*6^5 using each base only once

Can you me find the missing length. i attached an image.

Using the figure below, select the two pairs of alternate interior angles.a: point 1 and point 4 b : point 2 and point 3 c: point 6 and point 6d: point 5 and point 7

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.)