This isn't my best subject in geometry

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

At 6 1/2 cents per pound of string beans how much does 7 pounds cost

Ineed big ! the cost of a school banquet is $25 plus $15 for each person attending. create a table, sketch the graph, and write an equation in slope-intercept and point-slope form that gives total cost as a function of the number of people attending. what is the cost for 77 people?