If you double the input of a function and it results in twice the output

Answer pls man im trying to get out of summer school

Due to bad planning, two of the local schools have their annual plays on the same weekend. while 457 people attend one, and 372 attend the other, only 104 people were able to attend both. how many people went to at least one play?

What is the point slope form of a line with slope -5 that contains point (2,-1)