If 19.50$ was for 15.249 of gallons of gasoline what's the unit rate

Candy lives in the center of town. her friend darlene lives 28 miles to the east and her friend dana lives 21 miles north. approximately how far do dana and darline live apart ?

X+ y = 5 ; x - y =3 solve using linear combination

The circle below is centered at the point (3, 1) and has a radius of length 2. what is the equation?