The other dog's age is "x". Rex's puppy is 5 years less than "x". SO...
x-5.
Understand?
Move all terms to the left side and set equal to zero. then set each factor equal to zero .
x = - 6 - y
______
4 + r
Diameter is 18
radius is half of diameter so 9
area is radius*pi ^2 which is 88.83
circumference is diameter * pi so 18*pi = 56.55