Use the discriminant to determine the number of solutions to the quadratic equation −81a2+90a−25=0

Which logarithmic equation is equivalent to the exponential equation below? e^a=55(you will receive 34 points)

The circumference of a circle is 5 pi cm. what is the area of the circle?

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online