Solve by substitution.
y=x+3
y=5x-5

Here you have two linear equations for 'y.'  Since you are to use the substitution method, replace 'y' in the first equation with '5x-5' from the second equation.  This eliminates 'y' and gives you a single equation in 'x.'  Please solve this equation for the numeric value of 'x.'

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