Who can do this rn maths

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

Does anyone know how to do geometryme with this problem

Jason went to an arcade to play video games. he paid $2 for every 11 tokens he bought. he spent a total of $16 on tokens. which equation can be used to determine,t, the number lf tokens jason bought