X=-4
Y=4
The horizontal (left to right) line represents the x-axis!
The vertical (up and down) line represents the y-axis!
All are congruent. Congruent means identical in size or shape. the different markings on the two shapes show that they are congruent. I can’t fully see number 10 so I can’t say it that one is or not
Number of strings =

= 21 x 21 x 21 x 21 x 21 x 5 = 20 420 505
Answer: 20 420 505