I am having trouble on these problems. An explanation would be great for me to complete the rest of the worksheet, as I would have a guide. Any help would be greatly appreciated!

Aline has a slope of 1/4 and passes through point (0.4,-1/2). what is the value of the y-intercept?

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

Identify all the cases where non-probability sampling is used when attempting to study the characteristics of a large city. studies on every subject in the population divide a population in groups and obtain a sample studies with a limited amount of time demonstrate existing traits in a population studies with the nth person selected