How to Answer this Math problem?

Pls. Help

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.)

Me! i'm really confused the isosceles trapezoids, abcd and efgh, are similar quadrilaterals. the scale factor between the trapezoids is 2: 3, line gh = 6 centimeters, line ad = 8 centimeters, and line ab is three times the length of line dc . use complete sentences to answer the following prompts and include all of your calculations in your final answer. a. write a similarity statement for each of the four pair of corresponding sides. b. write a congruence statement for each of the four pair of corresponding angles. c. determine the perimeter for each of the isosceles trapezoids.

Which function has an inverse that is also a function? a. g(x) = 2x-3 b. k(x) = -9x2 c. f(x) |x+2| d. w(x) = -20