Помогите пожалуйста !!!

1)
$\displaystyle \frac{ \sqrt[6]{a^3 \sqrt{a}}}{a^{1/4}}= \frac{ \sqrt[6]{a^3*a^{1/2}}}{a^{1/4}}= \frac{ \sqrt[6]{a^{3+1/2}}}{a^{1/4}}= \frac{ \sqrt[6]{a^{7/2}}}{a^{1/4}}=\\\\= \frac{a^{7/2*1/6}}{a^{1/4}}= a^{7/12-1/4}=a^{4/12}= \sqrt[3]{a}$

2)
$\displaystyle 8^{log_23+1}=8^{log_23}*8=8*2^{3*log_23}=8*2^{log_23^3}=8*3^3=216$

3)
$\displaystyle \left \{ {{2x-3y=-3} \atop {x+3y=-6}} \right.\\\\ \left \{ {{2x-3y=-3} \atop {2x-3y+x+3y=-3+(-6)}} \right.\\\\ \left \{ {{2x-3y=-3} \atop {3x=-9}} \right.\\\\ \left \{ {{2x-3y=-3} \atop {x=-3}} \right.\\\\ \left \{ {{2*(-3)-3y=-3} \atop {x=-3}} \right.\\\\ \left \{ {{y=-1} \atop {x=-3}} \right.$