What does the equation x2 + y2 = 16 represent as a region in the set of real numbers3?

Let us say that x and y are points that are located in the Cartesian coordinate. The sum of the squares of x and y gives the square of the radius of the circle. Therefore the equation x^2 + y^2 = 16 given that x and y are real numbers represent a Circle.

A circle has a general formula of x^2 + y^2 = r^2

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^