Does anyone knows the answer to this answer?

Which equation and solution can be used to solve this problem? thirteen less than a number is sixteen. 13-n=16: add 13 to both sides. the answer is 29. n+13=16: subtract 13 from both sides. the answer is 3. n+16=13 subtract 13 from both sides. the answer is 3. n-13=16: add 13 to both sides. the answer is 29.

Find the solutions for a triangle with a =16, c =12, and b = 63º

Cd is the perpendicular bisector of both xy and st, and cy=20. find xy.