How to find the y intercept when the slope is a fraction

Draw a tape diagram to represent each situation.for some of the situations,you need to decide what to represent with a variable andre bakes 9 pans of brownies.he donates 7 pans to the school bake sale and keeps the rest to divide equally among his class of 30 students

A50% increase followed by 33 1/2% decrease

What is the value of the product (3-2i)(3+2i)?