Find a solution to the linear equation 13x+y=26

Oscar and julie ashton are celebrating their 15th anniversary by having a reception hall. they have budgeted $4,500 for their reception. if the reception hall charges a $90 cleanup fee plus & 36 per person, find the greatest number of people that they may invite and still stay within their budget.

Which geometric principle is used to justify the construction below?

Simplify the following expression 48^1/2