Задание номер 507. Заранее спасибо!

А) $\left \{ {{3( \frac{1}{3} x-1) \leq - \frac{1}{2} (2x+1)} \atop {2x-3 \geq x+4}} \right. \left \{ {{x-3 \leq -x- \frac{1}{2} } \atop {2x-x \geq 3+4}} \right. \left \{ {{2x \leq 3- \frac{1}{2} } \atop {x \geq 7}} \right. \left \{ {{2x \leq 2 \frac{1}{2} } \atop {x \geq 7}} \right. \left \{ {{x \leq 1 \frac{1}{4} } \atop {x \geq 7}} \right.$ - нет решения.
б) $\left \{ {{ x^{2} -2x \geq 1} \atop {- x^{2} +6x \leq 9}} \right. \left \{ {{ x^{2} -2x-1 \geq 0} \atop {- x^{2} +6x-9 \leq 0}} \right. \left \{ {{(x-1+ \sqrt{2} )(x-1- \sqrt{2} ) \geq 0} \atop {- (x-3)^{2} \leq 0}} \right. \left \{ {{x \leq 1- \sqrt{2} } \atop {x \geq 1+ \sqrt{2} }} \right.$