Any girls on this app

Which math sentence can be used to determine if the triangle is a right triangle?

Find the maximum value of p= 4x + 5y subject to the following constraints :

The ivring berlin learning center would like a possible net profit of $650,000 on its new resource manual it sells to schools. the fixed costs for producing the manual are $780,000 and the variable cost per package is $19.85. if the estimated unit sales are 1,250,000 units, what selling price unit should the ivring berlin learning center try?