Determine whether the lines given in each box are parallel, perpendicular, or neither

Which of these people has balanced their checkbook correctly? oa. gary: the balance in his check register is $500 and the balance in his bank statement is $500. b. gail: the balance in her check register is $400 and the balance in her bank statement is $500. c. gavin: the balance in his check register is $500 and the balance in his bank statement is $510.

Anyone know? will mark brainliest if you're correct!

Use the elimination method to solve the systems of equations.choose the correct ordered pair. 7x+4y=39