Proving 4 right angles

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

At a kentucky friend chicken, a survey showed 2/3 of all people preferred skinless chicken over the regular chicken. if 2,400 people responded to the survey, how many people preferred regular chicken?