Brainlist if correct please it’s important

Which best explains why this triangle is or is not a right triangle?

Acarnival sold tickets for $1.50 for adults and $1.00 for students. there were 54 tickets sold for a total of $70.50. write a system of equations to represent the number of adult tickets,x, and the number of student tickets,y. find the solution and explain what it means. i'll you if you me

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?