Compare . What does it mean ? What is happening?
Please help me :( !

X+y=-4 x-y=2 use elimination with adding and subtraction

Car a and car b were in a race .the driver of car b claimed that his car was twice as fast as car a

Amayoral candidate would like to know her residents’ views on a public open space before the mayoral debates. she asks only the people in her office. her co-workers are an example of a census population convenience sample simple random sample