Someone answer this for me and explain how to solve

3(10x-y)-5(x-y^2) need this solved asap

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.

Which of the following constants can be added to x2 - 3x to form a perfect square trinomial?