Решите 1075 пожалуйста

a)
$\left \{ {{3(x-5)-1=6-2x} \atop {3(x-y)-7y=-4}} \right.$

$\left \{ {{3x-15-1=6-2x} \atop {3x-3y-7y=-4}} \right.$

$\left \{ {{3x+2x=15+1+6} \atop {3x-10y=-4}} \right.$

$\left \{ {{5x=22} \atop {3x-10y=-4}} \right.$

$\left \{ {{x=4,4} \atop {3x-10y=-4}} \right.$

$\left \{ {{x=4,4} \atop {3*4,4-10y=-4}} \right.$

$\left \{ {{x=4,4} \atop {13,2-10y=-4}} \right.$

$\left \{ {{x=4,4} \atop {10y=17.2}} \right.$

$\left \{ {{x=4,4} \atop {y=1,72}} \right.$

б) Вот с этим решением я не очень уверенна
$\left \{ {{6(x+y)-y=-1} \atop {7(y+4)-(y+2)=0}} \right.$

$\left \{ {{6x+6y-y=-1} \atop {7y+28-y-2=0}} \right.$

$\left \{ {{6x+5y=-1} \atop {6y=2-28}} \right.$

$\left \{ {{6x+5y=-1} \atop {6y=-26}} \right.$

$\left \{ {{6x+5y=-1} \atop {y=4 \frac{1}{3} }} \right.$

$\left \{ {{6x+5*4 \frac{1}{3}=-1 } \atop {y=4 \frac{1}{3} }} \right.$

$\left \{ {{6x+21 \frac{2}{3}=-1 } \atop {y=4 \frac{1}{3} }} \right.$

$\left \{ {{6x[tex] \left \{ {{6x=-22 \frac{1}{3} } \atop {y=4 \frac{1}{3} }} \right.$

$\left \{ {{x= \frac{67}{18} } \atop {y=4 \frac{1}{3} }} \right.$ =-21 \frac{2}{3}-1 } \atop {y=4 \frac{1}{3} }} \right. [/tex]