Okay so, i'm working on rational and irrational can someone me find out why 27.5 is a rational number?

Rational numbers are numbers (positive or negative) that can be a decimal as long as the decimal is not repeating (terminating). Hope this helped :D

X^2 - 4x +(4/2^2) + y^2 + 8y + (8/2^2) = -4 + (4/2^2) + (8/2^2)(x + 2)^2 + (y + 4)^2 = -4 + 4 + 16your center is (-2, -4) and the radius is the sqrt of -4 + 4 + 16 which is 4