4.2 Show that the simultaneous equations $f(x_1, x_2) = 0$, where \\
$f = (f_1, f_2)^T$, with \\
$f_1(x_1, x_2) = x_1^2 + x_2^2 - 25$,
$f_2(x_1, x_2) = x_1 - 7x_2 - 25$, \\
have two solutions, one of which is $x_1 = 4$, $x_2 = -3$, and find the \\
other. Show that the function $f$ does not satisfy the conditions \\
of Theorem 4.3 at either of these solutions, but that if the sign \\
of $f_2$ is changed the conditions are satisfied at one solution, \\
and that if $f$ is replaced by $f^* = (f_2 - f_1, -f_2)^T$, then the \\
conditions are satisfied at the other. In each case, give a value \\
of the relaxation parameter $\lambda$ which will lead to convergence.
