Amanda ate breakfast at a restaurant. The bill came to $64. She left a 15$ tip, how much was the tip?

How do you convert 1.27 to a percentage

I'm confused on this could anyone me and show me what i need to do to solve it.

For problems 29 - 31 the graph of a quadratic function y=ax^2 + bx + c is shown. tell whether the discriminant of ax^2 + bx + c = 0 is positive, negative, or zero.