Heron's method/7/Start member 3/3 Steps/Exercise

Do the first three steps in Heron's method to compute the square root of ${}b=7$ with initial value ${}x_{0}=3$

(so the approximations

{}x_{1},x_{2},x_{3}

for

{}{\sqrt {7}}

shall be computed; these numbers have to be given as fractions reduced to lowest terms).