How do i even solve this? so confused? o_o

You are at a restaurant and owe $38 for your meal. you want to leave a 20% tip. how much will your tip be?

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

(05.03 mc) part a: explain why the x-coordinates of the points where the graphs of the equations y = 4x and y = 2x−2 intersect are the solutions of the equation 4x = 2x−2. (4 points) part b: make tables to find the solution to 4x = 2x−2. take the integer values of x between −3 and 3. (4 points) part c: how can you solve the equation 4x = 2x−2 graphically? (2 points)