What is the answer to 0.64/-3.2

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

Gail is making costumes for a school play. each rabbit costume needs one and one half yards of white fur fabric, a yard of blue striped fabric, and a quarter of a yard of pink felt for the ears. g? ail needs to make eight rabbit man yards will she need, for the white fur fabric, blue striped fabric, and pink felt?

The sum of two numbers is 86, and their difference is 20. find the two numbers