Please please help !!!

What number should be added to both sides of the equation to complete this square? x^2-10x=7

Angela rode his bike around a bike trail that was 1/4 of a mile long he rode his bike around the trail 8 * angelo says he wrote a total of 8/4 miles to russell says he's wrong and he actually and says that he actually wrote to my who is corrupt use words and trying to explain how you know.

Write a story that matches with the expression 42x-5 pls hurry