Help I need help I will make u a brainlist

Acompany is testing in comparing to lightbulb designs the box plot shows the number of hours that each lightbulb design last before burning out which statement is best supported by the information of the plot

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

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)